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[ you shouldn't have done that ]

Chapter Text

The Royal Scientist is not a carpenter.

He is not an architect of child-sized coffins, he is not a mortician, and the care and feeding of human SOULs is not his area of expertise by any stretch of the overly-optimistic imagination. He has made this abundantly clear to the king, but Asgore continues to paw and plead, as if that will change anything. A well-intentioned maneuver, but ultimately a pointless one.

Their views tend to differ on that account.

What the king calls hope, his employee calls stalling. What Asgore calls tenacity, the Royal Scientist calls an inability to recognize hopeless circumstance. Asgore calls it trust, and grief, and determination. It is folly and a poor man’s solution, at best. And so it goes.

Brevity is the soul of wit, they say, but it is also the essence of innovation. Asgore’s requests are met with an indication of the affirmative - sometimes encouraging, but most often not. The king can suspect nothing while one is intentionally vague. He is, indeed, working on removing the barrier that keeps monsterkind trapped, in a roundabout manner of speaking. But perhaps “remove” isn’t quite the word.

He adjusts the spectacles on the ridge of what a skeleton might call a “nose,” squinting his good eye at the wisp of light hovering in the center of the glass container. It pulsates faintly, still, persistent as its unique human properties allow. Humans, it seems, do not turn to dust when the host bodies die. They do not simply fade to swept and scattered like ashes. The seeping of red over the rocks of Hotland had been shocking, for some, but for one who’s seen this particular happenstance many times before, it is nothing, as they say, to write home about.

Were his sense of humor not shriveled and drier than the air in this volcanic wasteland, he might have laughed at that poor joke. One becomes accustomed to the red after a time. Whether it is blood, or rock, or magma, or, in some cases -

He sighs and dashes thin metacarpals across the topmost file in the stack left on his erstwhile assistant’s desk. Were he capable of screwing up his features in distaste, he would have likely done so as soon as that slightly-sweet scent wafted in his direction. The rules of “no food or drink in the workspace” are once again wasted, it seems. Someone is rather unfortunately adept at smuggling all manner of condiments into the lower laboratories.

He shakes his head with a snort of something resembling wry fondness. More trouble than he’s worth, this one. Any of them, if he’s honest with himself. Is that not something he prides himself for expressing, with articulation and sharp regularity? Precision, objectivity, a level head and a calm detachment from his surroundings to prevent the state of psychological disarray the experts like to call “compromise.” Yet the work laid out before him is not for one monster alone. The equations left on the abandoned desk are sloppily done, but correct, every one. He flips through the remainder of the files, one eyesocket ridge canting upward in mild intrigue. Either this one excels at mental math or he excels at shorthand - or both, possibly. Neither of them were things he made a point of noting to his superior.


He closes the files and slides them back into place. They are not for him. Not yet.

He rubs the bones of his fingertips together pensively. He’d proven himself easily enough with the success of the great crackling CORE and a promise of virtually limitless energy, but that had not been his area of expertise. He would never admit it to anyone, as it would be a feat in and of itself for someone to get him to admit anything, even to his closest confidants that spend their days sequestered down here with him, but the CORE had been, at its core (he groans), a mistake. A failure.

Its intention had not simply been to generate energy, but to convert it into something tangible and workable as well, and in that purpose it had failed utterly. It could supply the power needed to keep the Underground running as it did, but that was the extent of its abilities. He was praised for his creation, and he had waved each commendation aside.

He returns to his blackboard, sectioned off in its own specific area of the lab, its contents privy to no one but its sole owner. Without hesitation he wipes it clean of all of last night’s scribblings with a careless wave of his hand, that sheds the chalk dust easily and lets it powder down onto the floor.

classify: type ii causal structure violation

His good eye narrows into a hollow slit. Chart it. Cut it. Divide it. Simple and clean, deviating from the predetermined (a troublesome term and an inaccurate one, but he has nothing better) and onto the desired.

Best not to implement the changes personally, no. That will simply muddle the timeline and split it into too many potential branches, all vying for their inclusion into reality. Better to orchestrate them from here, and ensure that all chosen variables will fall into place as desired. Retrocausality is too tricky an algorithm to be granted free reign upon monsterkind’s future - or, in this case, past.

The chalk grinds into the chalkboard, white on black, carving out the limitless notations and characters whose meaning only he knows. Encrypted and coded a dozen times over, into an exact language he has ensured only he knows how to interpret.

It will not be over when they tear themselves free of the barrier.

It will only be over when they are never trapped behind it in the first place.

Chapter Text

The roar of steam and the clanging of pistons almost drowns out the patter of little yellow feet racing to through Hotland, but some people happen to have employers that are scarily good at interpreting vibrations in the ground, or whatever D̶̷̲̅ʀ̶̷̲̅.G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅ manages to do without looking up or looking at anyone at all, because he’s a genius and genuises have to maintain that strategic aura of mystery, she guesses, for the sake of their reputation. Maybe he’s got a super-secret tragic backstory that no one can or ever should unlock. Or maybe he’s just paranoid, but that doesn’t sound nearly as thrilling. Alphys doesn’t do thrilling, typically, or at least not in the dark and suspenseful sense. She prefers her fiction (and nonfiction!) to be cute and friendly and blissfully romantic, and seeing as real life is currently none of those things, she’ll have to settle by immersing herself in every new episode of Mew Mew Kissy Cutie that drifts down here as recompense.

The laboratory is closed as always, reducing Alphys to banging on the doors until gradually they slide open with a pneumatic hiss of air. The lab smells like it always does - dry and stale and sterile, with the lingering tang of some kind of antiseptic that makes her nostrils itch and twitch with discomfort.

But she’ll take it, because it’s the smell of home! Well, it’s sort of the smell of home. Maybe it would be if she actually lived here, like G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅ does, but then she’d have no time for Catty or Bratty or her beloved Kissy Cutie.

No one’s on the surface levels. Alphys makes a beeline for the elevator and taps one of the buttons with a nervous claw, glancing around furtively over her shoulders as if someone might show up any moment and reprimand her, even if she has every right to be here and signed a waiver and everything, she could break out the paperwork from her desk if she had to, because she works here and has full run of all the downstairs levels with one notable exception, and that’s because G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅ never lets anyone into that particular spot so it’s nothing to do with her.

(She tells herself, over and over, day after day. She’s a respected colleague, even if people don’t really know who she is. She’s got important work here.)

The lights aren’t on when the elevator groans to a rattle-y stop and she steps outside.

“M-morning!” she calls into the darkened interior. She squeaks in barely-concealed fright when a pair of disembodied skeletal hands materializes in front of her.

Third door to the right, they spell out, and fade again into nothing. He always did have the flair for the dramatic, didn’t he? He just had to magic up something appropriately flashy for something as simple as directions. This place can be a real maze, but she’s been working here for a ʏ̶̷̲̅ᴇ̶̷̲̅ᴀ̶̷̲̅ᴘ̶̷̲̅ ᴍ̶̷̲̅ᴏ̶̷̲̅ɴ̶̷̲̅ᴛ̶̷̲̅ʜ̶̷̲̅s̶̷̲̅ while now. She’s not that helpless.

The panels light up in flickering green text as Alphys passes them, but she always had difficulty reading hands. Even the simplified form of that language G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅ uses can be a struggle sometimes, especially once he really starts going, chattering off at light speed.

“Morning!” she says again once she reaches his room, as brightly as she can, as if that might illuminate the pervading dimness of the bleakly lit place. It’s not a question of funding, she’s pretty sure by now, but why G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅ insists on keeping this place in the dark is beyond her. Not technically, though. Technically, she’s very certain of how he manages to conserve the lighting and keep it so low, even if it makes her eyes hurt and her head ache from all the squinting she does. She’ll have to need glasses at the rate she’s going. But maybe they could be cute ones. Like, with glittery pink frames, and she could even get Sans to solder a little Mew Mew logo on the corners, maybe? He’s good at that kind of stuff.

Is it? Another pair of hands floats just behind G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅. He doesn’t even look up at her. I must have lost track of -

It takes her a while to decode that particular word.

- time.

“H-hey, me too!” She waves one claw, like, wow, totally not a big deal, look at them, all on the same level and everything! But god, she could never be like G̶̷̲̅ɢ̶̷̲̅G̶̷̲̅G̶̷̲̅Дᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅. All tall and dark and mysterious, sweeping around with that coat like something of a noir film. Somehow he manages to be ever stately and elegant, even in his movements, fluid like silk, or oil. Or something equally slippery.

You have not seen your associate, have you? he asks. He still doesn’t look up at her. Either he’s really wrapped up in his work, or - or, well, that’s probably the reason he’s not looking up, right? Definitely not any kind of, of personal thing, where he hates her guts or thinks she’s garbage or anything, I mean, he’d probably tell her to leave if that was the case and he hasn’t yet, so, they’re great, they’re all right, they’re on good terms and everything. Except he’s asking for Sans in that weird way where he doesn’t use his name? Maybe he likes Sans better. There’s some kind of solidarity there, maybe. Like a skeleton solidarity.

“Oh, you know him.” Alphys chuckles, and the noise dies partway past her throat. “Probably, probably sleeping in. Or, um, or taking one of his breaks.”

His good eye shuts, creasing momentarily in silent vexation.

Of course he is.

Oh. She knows that tone (can hands have a tone? Well, his do at any rate). That’s disapproval. He gets like that a lot. She can’t help but shrink a little in place, except there’s really nowhere to go. No convenient patch of quicksand she can sink into.

“Anything, um, anything I can help with?” she manages with a hopeful lift to her tone.

G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅ shakes his head.

She peers at whatever he’s working on. It’s another sheet full of things she can’t read, even going off what little she knows about hands. There’s something something quantum and something something something self-consistency, but she’d be the wrong person to ask on the specifics.

Good thing no one’s asking. Or caring. At all.

Not now, I think. Check upstairs.

It’s because she can’t speak in hands, isn’t it? Yet another thing he and Sans have in common, aside from the skeleton thing. The whole language issue. Did they come from the same place? Oh my god, are they related? The question stops her dead in her tracks for an instant before she remembers what she’s meant to be doing and scuttles back to the elevator and get to the surface level, the floor she’s selfishly totally reasonably begun to think of as “hers”. No one else really checks up here, except maybe Asgore, if he’s let inside. G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅ can stick to his own stuff, and Sans can add his effort to the pile when he feels up to it. But Alphys? She has her cybernetics. And that’s all she needs.


Honestly. Totally.

G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅ built the CORE all on his own. What’s he need her for? She knows technology back to front, putting together what needs to be put together in record time, but she’s not him. And everyone knows it.

Or everyone would if the Royal Scientist was at all a public figure. But he just stays cooped up in his laboratory all the time. She doesn’t even know if he goes outside, like, at all? But he must. He’s got to. Right? Right.

That would just be weird otherwise.

Seeing as G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅ evidently has no need for her (she will not take it personally, she will not take it personally, she will not take it personally, this is fine and normal and he has ever right to be standoffish and this is totally normal for him!), that gives her plenty of time for her pet project. She can’t shake the guilt of working on something so comparatively inconsequential while G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅ is busy trying to solve the central problem plaguing all of monsterkind below, but he did more or less dismiss her, and she came all this way, so she might as well get something done.

Usually it’s not difficult to get sucked into the flow of her work (it’s easy as bingeing the entirety of those twenty-or-so episodes of anime that get compiled onto the DVDs that occasionally drop into the garbage). The work days fly by. She accumulates the desired materials, iron and tungsten and the odd ingot of titanium if she can get her claws on it, and the energy from G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅’s CORE is more than enough to power the tools necessary in shaping each individual piece to her needs. Her latest invention is something a bit more ambitious, and a failure if you get technical about it, but - but! But it’s still a work in progress, which means success might be, one day, right around the corner. She just has to stay fixed on her goal, and it’ll work itself out! She has faith in her abilities.

Who’s she kidding.

No she doesn’t.

Alphys is lost in thought when she stumbles across a peculiar sight in her the lab. She peers at the snoring bundle in one of her swivel chairs, momentarily uncomprehending, until she recognizes it for who it must be.

“Sleeping - um, sleeping in?” She proposes the question quietly, a timid little whisper, but that’s enough to stir him. Eyesockets crack open, and there’s the wide grin she’s beginning to appreciate as characteristic of him.

“Heh.” He manages to get to his feet extremely fluidly despite not moving all that much, which has Alphys puzzled for a moment since that little maneuver didn’t look like it should’ve been possible at all? “Well, you know. Just taking a little catnap.”

He says it like its a joke, and Alphys stares blankly at him until he reaches out and lightly flicks a fingerbone at one of the figurines clustered on her desk, indicating Mew Mew (oh my god, does he know who she - wait, no, it’s the cat ears, that makes it kind of obvious, doesn’t it, obviously).

That’s her cue to groan and shake her head fondly.

“He’s asking for you,” says Alphys, with an inclination of her head toward the elevator.

“Who?” Sans seems distracted.

“You know who.” The name sticks in her tongue, a little bit.

“Oh. Right.” Is it just her, or does he seem a bit dejected? “Welp. Guess I’ll be down there soon.”

He sleeps here too, doesn’t he? Like G̶̷̲̅ᴀ̶̷̲̅s̶̷̲̅ᴛ̶̷̲̅ᴇ̶̷̲̅ʀ̶̷̲̅, he just has to stay inside all the time. Do they hate being outside, or something? She’s never asked, but it seems rather glaring a characteristic to be shared between them. That and speaking in hands on top of it, but they’re about as far apart in terms of personality as two monsters could be. Working hard and hardly working, respectively. Alphys is almost proud of that joke. It’s pretty much Sans levels of terrible.

“Don’t you ever go out?” she asks the question before she can really put a name to the impulse that draws it out, shooting it at the back of Sans’s skull as he heads for the elevator. He pauses.


“Why not?”

He shrugs.

She feels like he’s told her this before. But she’d remember if that were the case.

Wouldn’t she?

“But I’m preaching to the choir,” Sans is saying, and Alphys realizes she must have missed whatever his answer was. She blinks several times and gives herself a little shake to ground herself back in the present. Sans still isn’t looking at her. “Guess it’d really be more effort than it’s worth, though. Right?”

“R-right!” Smiles on, Alphys, come on. Where’s your brain today? She pastes on an anxious grin and nods enthusiastically. “D-definitely!”

Sans makes a vaguely amused little sound, like a chuckle, as the elevator doors whoosh open and he steps inside. It almost sounds too sad to be laughter. Does that even make sense?

She wants to latch her claws into that nagging problem of sense and how today hasn’t made any of it, cling tight to it and never let go. Some undeniable wrongness is hovering just out of reach and she can almost taste it, stinging and sharp like the burning smell of ozone hanging in the air, like the CORE, like the crackle of magic at bony fingertips and negative photon readings and a plunging nothingness reaching to the ceiling and hoarse laughter and the tinkle of breaking glass as something fragments and splits apart, because the more she thinks about it the less sense it













but she’s not trying to make a functional robot here, she’s trying to make a shell of one, which is an important distinction since that means the programming will be much simpler. It just has to function regularly, all the limbs bendable and not too fragile, and that’s something she knows how to do. Right now it’s just a vague boxy shape, but she can build off that, and anyway, she told them - him! him, she has to remind herself, him - it would just be a prototype the first time around. She’s good with robotics, but not that good, not immediately. She’ll have to build up to the more complicated stuff he wants, but he’ll get his new body. She’s the only one who can make it for him.

And maybe, once she’s managed it, maybe finally the king might take notice. The breath gets wispy in her lungs just thinking about it. The king - or even the head of the Royal Guard. The thought makes her claws shake so she hastily tries to divert it, but it’s no use now - she’s stuck on that mental image now, and oh god she’s just a grubby little lizard in a labcoat so who would care, especially the king or the head of the Royal Guard, which is way more important than anything Alphys could ever hope to achieve? Because that’s, that’s, that’s important. People actually care about that. That actually makes a difference.

But - but no, no, she’s getting ahead of herself. She can do this. She has to do this. She can be the next great Royal Scientist!

The position’s been vacant for years, after all.

Chapter Text

He watches the floor indicator tick lower and lower as the elevator sinks ever deeper into the earth. Higher heat, even higher pressure. Good thing he doesn’t have organs.

His grin’s unfaltering as ever when he steps out.

Darkness, darkness, and yet more darkness. The doc doesn’t like lighting up the place. He’s half-blind already, so what’s he got to lose from keeping the place in shadows all the time? Sans’s shin collides with the corner of a metal table, and he sighs. It’s not unbearable. It’s just annoying. And potentially dangerous, considering the kind of artificial fauna that gets grown here. But the doc courts danger like a rare, poisonous species of metaphor.

Sans waits in the doorway for a moment, inspects the nondescript walls, lets his eyesockets adjust to the uniform semidark. The old man doesn’t look up, so Sans drums his knuckles against the open door with the quiet click of bone tapping against metal. “You rang?”

Ah, and there they are, those twin hands materializing behind him in a puff of wispy magic and antilogic. Gotta love the basics. The doc always had a thing for negation. Negative space, negative time, subverting one’s own existence, amplitude desynchronization and dividing by zero, blinking in and out and making it so you never were. Makes his skull ache just to think about it, but that was never his speciality. That’s the doc’s job, even if it’s not supposed to be, technically speaking. Technically speaking he’s a one-monster barrier-breaking science team, with his up-and-coming protegee putting in her technological two-cents here and again. She’s good at what she does. Got her claws full managing it, but she’s good.

No one asks about Sans. Way it should be. Way it has to be? Way it was? Syntax is a hell of a thing, and he doesn’t find himself inclined to bend his mind trying to mangle together a halfway-comprehensible subjunctive. Not when time is fluid, or more appropriately, almost a plasmic kind of deal, when it can be chided into getting its shit together.

I did. The doc seems happy to see him. Happy as someone like him gets, at any rate. It’s not saying a lot, but that weighty, deep-run pall of focus lessens a hair, even if he still doesn’t look up. Obviously he can’t. His work is too important. I’ve made something of a breakthrough.

Sans enters the room fully, hooking one foot around the leg of the nearest stool so he sit across from whatever brand new thing the doc’s working on, elbow braced against the table, cheekbone propped up on the curled knuckles of one fist.

“You gonna take a break to go with that through?” he says idly, but the doc’s not listening. He’s too busy drawing those spindle-thin fingerbones apart in a faint flourish as he indicates the object on the table. And, ding-ding-ding, it looks like...a sheet of paper. Fascinating.

But Sans can’t resist. Keeping up the front’s too much work, and he’s damn curious. He leans forward, peering at it. He squints. He tilts his head to one side and studies the precise margins and diagonal markings for a solid minute.

Then he looks up.

“Looks like a spectrograph.”

The doc makes a dry little huffing sound that lands somewhere between amused and annoyed.

Incapable of recognizing the big picture as always. There’s that note of unmistakable fondness to the admonishment. The grin doesn’t fade - when does it ever? - but he can feel the little pinpricks of light in his eyes dilating incrementally at the obliquely insulting remark. Just because he can’t bend metatemporal fabric with a crook of his little finger doesn’t mean he hasn’t got his own specialities. He can index all the values he wants when it suits him, it’s just an awful lot of work to do the kinds of things the doc does on a regular, flashy basis. He’s gotta sign all the things he does with his own personal flourish, cultivating that aura of mystery and depthless knowledge he pretends he doesn’t enjoy.

But the doc excels on making him feel like a rank little schoolmonster. That one’s his specialty. One hell of a scientist, and the kind of guy who will never stop quietly lording that over you every second of every day. Even the days that never happened. But once you’re committed to that level of autolatry, hey, might as well go all the way.

You’re familiar with my work. I’ve been charting anomalies.

Sans nods, carefully saying nothing. Fancy doctor-speak for I like my science weird. Who doesn’t? The doc isn’t special in that sense.

“We don’t really get a lotta those down here,” he says with a shrug of one shoulder. The nonchalance probably sounds forced. It definitely sounds forced.

Of course not, the doc scoffs, which is why I created my own.

Something uncomfortable calcifies in the pit of him, and his eyes go blank with momentary shock.


He can’t even inflect it like a question. He should’ve anticipated something like this. He doesn’t appreciate being caught off guard, particularly by a variable he can’t predict.

A simple spatiotemporal desync. The doc flaps one hand dismissively, like a spatiotemporal desync is just standard babybones’ play and easy enough to just manufacture right on the spot, wholesale. But Sans’s spine’s gone rigid and he’s no longer slouching against the table.

The doc wanted him paying rapt attention. Mission damn well accomplished.

“What’d you do?”

I successfully recorded the anomaly, and all other self-fabricated instances. The doc keeps on going, indicating the undeniable spike in his graph that offsets the flatline up until the point in time that occurred negative point-five seconds ago.

Ugh. Negative time. So where does that put it? In the future? In the past? Did it never happen? Maybe it happened and then didn’t, the event that existed in absentia and now that it’s gone there’s no point in remembering. Was, wasn’t, should have, shouldn’t be, would have been would have had been would not have had been could not have had been will be won’t won’t won’t

Sans’s skull throbs. His eyesockets slip shut at the surge of displacement that tingles the marrow of his bones.

And if you compare the number of anomalous events detectable in the current timeline, the doc just keeps going, hands painted on the backs of Sans’s lids like this is standard stuff for him, and, yeah, he’s not wrong, it is, you’ll find that I’ve been successful in recording each instance.

“How, uh, how many events are we talking here, Doc?” Sans says weakly. There’s a fine sheen of sweat collating on the smooth ridges of his skull.

That hardly matters. Dismissive as always. Come on, doc, this is important. He’s good at what he does, the best even, but if he’s been ripping up holes in the quantum foam, that’s gonna leave a hell of a residue.

“You’re telling me you risked the fabric of spacetime to test a spectrograph?”

It is not a spectrograph. Of course, that would be his focus. Semantics. The remote possibility that anything Sans just said could be interpreted as a personal slight. And the anomalies themselves are contained.

“Contained how?”

The doc makes a frustrated sound, hands momentarily clenching into themselves before unclenching and returning to tracing shapes and letters.

They never existed.

Sans sits back down with a bump, feeling like he’s just run a twenty-mile marathon. Annoyance, anger, frustration - all taking way more effort than he has in him. He looks up at the doc wearily.

“Shouldn’t scare me like that, Doc.”

You worry pointlessly. The good doctor, contrarian genius that he is, has returned to tinkering with the bit of machinery to the left of the table, some complex thing, a mass of twisting chrome and repurposed instruments of human manufacture. It looks a little like a seismograph, but basic intuition would indicate that it’s the method through which the doc charted his little self-created spatiotemporal aberrations. He didn't notice it before now, which retroactively strikes him as a little odd. Perception filter, maybe?

Sans reaches over with one finger and slides the graph closer to him.

“How’s it track anomalies if they never existed?” he asks, deliberately casual.

The machine is immune to that. The derisive “obviously” goes unspoken, but Sans can hear it tacked on regardless. His eyes flick up from the graph to regard the doc in mild surprise and - it prickles to admit it, but admiration.

“You were able to isolate the meta variable?”

Despite every effort to sound only vaguely interested, he doesn’t quite succeed. The doc looks a bit smug as he realigns a fresh sheet of butcher paper to feed into the, dare he even think it? dead impressive piece of technology.

It took some very advanced quantum manipulation, but yes. The hands move faster and faster, a flurry of gestures, the only indication that the doc is at all excited that Sans at last seems to be catching on. It exists outside time and space, its own fixed point, unaffected by standard quantum decay. Any changes we effect upon it will be permanent, even if we were to, say, reset our coordinates based on a four-tuple value of of zero point zero point zero point zero.

Zero, zero, zero, zero...ah.

“Is that even possible?”

That remains a work in progress. He should sound disgruntled at having to admit a shortcoming of his, but Sans supposes he’s still too delighted over his own success. But I believe it is the next step.

“How do you even interact with it, then?” Sans watches carefully, but the doc’s hands never touch the machine. Or rather, the ones attached to his body don’t. The floating pair behind him descend to make minute adjustments. He hadn’t realized the doc had modified his central means of communication to be capable of motor function.

Some things already exist outside of time. You know that. The shadow of a great looming skull flickers behind the doc for a hair of a moment, maw gaping wide and eyes aglow. The silhouettes of a dozen femurs line up behind it, and then fade into nothing. Well, not nothing. Sans isn’t sure there’s a word for their state of being yet.

“You got it to stick to something inorganic?” All right, well now he’s definitely impressed despite himself.

Yes. Now we need only examine how best to expand upon it. The paper hisses as it’s inserted into the machine. Non-matter doesn’t enjoy interacting with matter, Sans supposes, unless the doc had the foresight to make the paper immune to time, so to speak, as well. But maybe that’s not his priority just yet.

For instance, how to scale back our own four-tuple values.

“Sounds like work,” says Sans, his jaw popping in a yawn. It also sounds impossible. He’s overdue for a nap. Overdue for another nap.

I don’t understand how you intend to integrate into society if you don’t apply yourself, the doctor says with a sigh and a shake of his head.

“Simple.” Sans shrugs, spreading his arms wide. “I walk out the front door. Problem solved.”

No, the doctor snaps, shedding all pretense of friendliness. Do not even joke. You know why you cannot do that.

“Potential catastrophe, temporal runoff, negative p-values, the big fat null hypothesis.” It’s easy to mask his disappointment. “You made that pretty clear, Doc.”

Then do not mention it again.

Can’t even take a joke.

When you work as closely with spacetime fluctuations as we do, we cannot risk the transfer of such a...unique property. Is he still scolding? He’s still scolding. The havoc that would wreak is unthinkable.

“Doc. I know.” Come on, Sans, be disarming. But he’s already grinning wide as ever, even if the strain of maintaining composure has sweat beading on one side of his skull. “It was just a joke.”

Do not. Mention it. Again.

Seems awfully preoccupied with the state of monsterkind for someone who never steps out to ingratiate himself with any of them, with the exception of Alphys. But she proved herself worthwhile, didn’t she? An intriguing prospect, a meaningful risk.

“Where’re you going with this, Doc?” he asks at last. “Messing with the state of things.”

He has a hypothesis, of course, and he could be wrong about that hypothesis, but given what he knows about the work here, he doubts it. Negation is in and of itself a dubious science, like filtering antiparticles through a funnel made of tissue paper and packing tape. The doc’s methods aren’t exactly one hundred percent stable, but it’s doubtful there’s any means of rectifying that when you’re autoclaving nonexistent materials into something compact and workable on the tangible plane.

One corner of the doc’s mouth twitches in a sly smirk. You’ll see.

That look generally means nothing good.

“You know this isn’t my area, Doc.”

I’m aware of that, yes.

“Then I’ll leave you to it.”

The doc doesn’t respond. Never needed his help after all, did he? No, he just needed someone to share his breakthrough with, because Alphys is, what? Just too normal for him?

He never pretended to fathom what goes on in the doc’s head. He never wants to.

That’s not his job.

Chapter Text

“I miss home,” says Sans, completely out of the blue, chin propped on the curled knuckles of one fist.

The doc isn’t listening. He can tell because he just says, interesting, which is what he says when the subject is everything but.

How long can he stretch this out? Sans leans back in his chair, feet up on the metal desk, hands folding behind his head.

“Yeah, I really miss the way the mushroom king celebrated the new year with his merry band of misfit toys.”

He counts the seconds and gets to thirteen before the doc looks up, a frown briefly marring his expression.


“Hm?” says Sans.

Did you say something about mushrooms?

“Nope,” says Sans.

The doc hesitates only a moment before resuming his work. Odd.

Yeah. Odd. The distraction is brief, the entertainment factor even more so. Bored once more, Sans lets his stare wander about the laboratory, the numerous instruments whose purposes he can only guess, the tools of the doc’s trade or the ones he designed himself. Spidery silver things that look like a good gust of wind would shatter them, bulbous glass receptacles filled with fluids of varying viscosity, countless others he can’t put a name to. And among the clutter, a single, undeniably fake ficus plant in a little plastic pot. Alphys’s note is still attached to it, written with one of her glittery pink gel pens.

”To the best doctor ever!! ♥ Alphys!”

Doc being the doc, he’s yet to acknowledge that the plant even exists, let alone that Alphys went to any lengths to brighten the place up. It was a thoughtful effort. Utterly wasted on the doc, but thoughtful. At least Alphys had the foresight to realize that a real plant would die in a matter of days down here thanks to the fatal combination of the darkened laboratory and the doc’s own profoundnegligence.

The doc makes a faint, satisfied sound as the pieces of machinery in his hands snap together with the blitzing click of two components aligning.

An empty flask slips from its shelf and smashes on the ground.

Sans stares at it oddly. He’s pretty sure he didn’t do that.

Your attempts to distract me are growing desperate, I see, says the doc, dry and amused.

“That wasn’t me,” says Sans, but it falls on deaf ears. Must’ve figured Sans pulled one of his gravitational tricks. Blue magic is tough stuff, and the doc’s no expert at that particular science, even if Sans can boast a profound talent in the art. But using it also requires effort, and effort requires motivation, and he simply can’t be bothered the vast majority of the time. Including now.

Bringing them back to square one.

Doc just keeps tinkering, like he always does. Hyper-focused on a singular goal, which is to do...something involving time Sans isn’t one hundred percent certain of, and is frankly a little scared to ask about for a multitude of reasons. The king thinks the doc’s working on breaking the barrier like a good little scientist. The king really needs to work on his judgment of character, and also the level of trust he puts in his scientist...s.

The king needs to work on a lot of things. But someone else is gonna have to be the one to tell him. A couple of skeletons working closely with time, causality, effecting the cause before it’s been caused, can’t just go out and mingle with the public like they’re not a pair of walking, talking, potential temporal hazards.

The doc’s doing his doc thing, and Sans takes the opportunity to slip out and make for the elevator. He could work on a dozen other things, dozens of sidelined pet projects, or start dozens more. But that sounds like work, and he’s got better things to do with his time. Things that involve what the doc will dismiss as sleeping.

The tarnished silver doors hush quietly open and he ambles inside. His fingertips skirt over the wall of buttons mounted beside the doors. Ground floor’s off-limits, isn’t it, Doc? The button flashes red and locks up when he applies pressure to it. The doc’s smart, coding that kind of fingerwidth recognition into all his tech. Clever. He’s had to be. He’s not known for his oversights.

Sans hits the button just beneath the ground floor. Can’t go out, so he’ll have to settle for the next best thing, huh?

He misses home. He misses places that aren’t a darkened laboratory in Hotland, subterranean levels beneath the subterranean levels, levels that aren’t numbered and don’t exist and can’t be accessed by elevator. Levels that not even Alphys knows about, that not even Sans is meant to get into.

The doc’s good, but Sans is good in other ways. The doc’s specializations are in time, the absence of it, the foundations of it, the negation and cessation and reanimation of existence. Laziness and its manifold extrapolations, well, those are his area. The doc likes to keep his more dangerous inventions in those folds of spacetime that have gotten so twisted, so snarled up and torqued around one another, that negating them entirely is the only way to keep the quantum fabric from hewing itself asunder one of these days. Bang, convenient little spatial pocket, isolated from everything else. Infinite storage space. Perfect for those big honking skull blasters of his, the elegant defense mechanism - the doc’s words, of course - he used to impress Asgore and get himself promoted to Royal Scientist.

Cracking the doc’s lockout protocols is a lot like biohacking, or any kind of hacking, if Sans is honest. It’s not about formulating a countermeasure strong enough to slam through the walls of carefully aligned code. It’s about poking and prodding and hunting down the gaps in the code, the fragile bits, exploiting them until they let him in. Loopholes. They’re the lazy skeleton’s best and only hand.

Main problem: the doc’s work is airtight, concise, practically hermetically sealed in its own grid. He knows how to unravel and reravel all those ones and zeroes, bind them together, and make it all look damn good while he’s doing it. There’s not an unnecessary program out there. The doc loathes anti-necessities. Sloppy work is ten times easier to exploit, which is why Sans has such a damn problem subverting the groundwork of the doc’s lockouts. Because there isn’t anything to exploit.

In theory.

The thing doc doesn’t realize is the varied gaps and crests in the quantum foam don’t just serve as little helpful pockets to slip his hidden nothings in and out of. A couple nudges in the right direction, lining all those aberrations up in just the exact way, and they can make a streamlined path cutting directly to the marrow of things. Heh. Thanks to the doc’s fiddlings, there’s more than enough untethered packages of antispace to go ‘round.

The elevator reaches the floor just beneath the ground level - underground level, rather - and Sans shoves his hands into his pockets, rocks back on his heels, and searches out the particular thing he’s looking for.

Here we go.

The next minute, he’s gone.

The “surface” lab is pretty standard, but the main appeal to it is that it’s a whole lot brighter. Not like the cool, dark lower levels with their sickly greenish tint and spotty lighting and sputtering electrical grid. Clean white-tiled walls and floors, tables full of monitors and the doc’s various shuffled documents. All the stuff someone like Sans isn’t supposed to be looking at. He casts a disinterested look over the crisp stacks of papers written in hands. Alphys comes and goes from this level as she pleases, but she grew up in the Underground, and she’s got only a rudimentary understanding of hands, as far as he knows. Sans, on the other hand…

He chuckles softly to himself.

Nice lockout, Doc.

Sans meanders. Not enough emptiness up here for him to duck on outside, but the change in scenery is enough for now. He doesn’t get these opportunities often. Good to make the best of them.

Someone’s left their computer on. A computer coated with several sparkling, lurid pink stickers, several sporting a cat-eared human sort of character winking cheerfully at the observer, mouth frozen in a perfect, plastic smile. Sans hits the spacebar and jolts the machine out of its screensaver. Alphys had the foresight to close down everything she’d been working on, at least. Unlike the doc, who’s left his work scattered everywhere for the world to see. The world being, in this case, a single skeleton with a knack for finding loopholes in grossly overcompensating security measures.

Sans drops into the swivel chair and cards through the innards of her computer’s programming with a few adept clicks and keystrokes. There’s quite a few files of something called Mew Mew Kissy Cutie on here.

Once he’s done painstakingly replacing the contents of each Mew Mew file with clips from an assortment of horrifyingly dull wildlife documentaries, Sans checks the clock mounted high on the wall. Huh. Doc’s been at it for a few hours now. Busy day?

He debates the merits of returning to the lower levels, and decides against it.

Like he said. Doesn’t get these opportunities often.

The doc’s notes don’t contain anything Sans hasn’t already read. Time dilation fields, blah blah, chronic hysteresis, yadda yadda yadda, all very fascinating if it weren’t all conceptual. The doc’s gotten good with his deft quantum manipulation, but Sans is fairly certain that temporal shift without a corresponding spatial desynchronization is beyond even the doc’s considerable expertise. In fact, he’s certain that’s beyond anyone’s expertise. Anyone with that much power would be in total control of theirs and everyone else’s timelines without consequence.

Sans carefully gathers all the notes together again, aligns them back into their neat stack with a few sharp taps against the tabletop.

The doc’s a mess.

A workaholic, self-autolyzing, overconfident, emotionally distant mess with a pathological need for control that supersedes the ordinary, the possible, and the theoretically impossible.

He’s also all Sans has got, and vice versa.

Sans shoots one last look at the door to the outside that won’t open for him. In the next moment, he’s gone again.

Chapter Text

An empty flask slips from its shelf and smashes on the ground.

Sans stares at it oddly. He’s pretty sure he didn’t do that.

Ah! says the doc, evidently delighted about something, and he glances at Sans, enthusiasm swirling up behind his spectacles.

“That wasn’t me,” says Sans, puzzled.

You didn’t feel that? says the doc. His coat swirls as he abruptly turns back to whatever it is he’s working on, some splayed-out array of glinting machinery imbued with an unearthly shimmer.

“Feel what, Doc?” Sans says, ignoring the acute sensation that they’re both having extremely one-sided conversations here.

We’ve done this before.

Well, that could mean anything. Sans eyes the doc warily as he watches him flit about the room, worked up to a state of excitement Sans is pretty sure he can say he’s never seen before. The doc doesn’t do excited, not like this.

“You wanna run that by me again?” he asks, endeavoring to keep his tone steady as the doc peers at his not-spectrograph, his good eye lighting up.

You, me, in this very lab. Sans has to squint to keep track of the doc’s hands, signing in a wide flurry of bright, fast gestures. The shape of his fingertips almost feel burned into his eyesockets by the end of it. A glass landed on the ground. I told you your attempts at distraction were for naught.

The pace and flow of his speech slows, and the doc peers at Sans suspiciously. You don’t remember?

“You, uh, might wanna get some fresh air, there, Doc,” says Sans, tapping at the side of his skull with a finger. “I think all this work down here’s gone to your head.”

It’s a halfhearted attempt, and the doc sees right through it. The monster who invented the CORE, the ingenious method of channeling energy throughout the Underground, the monster who devised the most cunning, powerful attack formations Sans had ever seen, blasts issued from skulls that not even King Asgore would dare employ to his advantage - cracked, just like that? No. He’s onto something, even if Sans doesn’t have the insight to see exactly what he’s on about just yet. He’s created anomalies before, and worse. This might just be another of them.

Emphasis on “might”.

We’ve done this before, the doc insists, his hands cutting through the air with a particular edge, flinted and frustrated. I’ve done it. I successfully set us back - by a number of hours, perhaps even a full day.

“All right, all right.” Sans raises both hands, palms out, in a nervous, placating gesture. “I believe you, Doc, all right?”

He just doesn’t get it. How’d he set them back? Who manages to scale back their own four-tuple values to a particular origin point and concurrently do the same for everyone else, presumably? How’d he define his own origin point? And, more importantly, is he capable of undoing what he just did?

Sans scratches the back of his skull.

“You know all your warnings about temporal runoff?” Sans says, the bony ridges over his eyesockets knitting down in a frown of concentration. “I think that might be what’s going on here, Doc.”

Anti-chronologic residuum. Comes with the territory, allegedly. Too much running into that kind of overly-conceptual, paradoxical stuff, and you end up with a hell of a logjam of detached, anomalous material with nowhere to go but the nearest thing - the doc, in this case, and most cases, considering what he deals with on a regular basis. Breaking time, breaking space - he must’ve set them back in space and time concurrently, otherwise he’d be mangling the curve irreparably, wouldn’t he?

A handy-dandy, walking, talking anomaly.


Very yikes.

Possible, says the doc with a contemplative nod. Highly probable, in fact.

“So what’s your t1 value round to, anyway? Since we’re assuming this is still working within the bounds of a logical timelike curve, yeah?”

Defined by singular actions, the doc says, his motions curt and rapid. The glass falls. It breaks on the ground. That signals an impending windback to a pre-established origin point.

“Okay,” says Sans, “but how was it established? Why this particular point? Do we have a timestamp? Anything?”

Position p1 at t0 can only go so far before it’s pulled back to t0, likely without any mnemonic retention if what the doc’s saying is true. The doc remembers - he’s got the advantage of being a uniquely time-independent aspect. Sans doesn’t have that luxury. Whatever he did after this during the last closed loop, it’s confined to a strictly t1(c(t1 - t0)) space within the undefined duration of time they have at their infinitary disposal.

“Kind of a slap in the face to causal determinism, isn’t it?” Sans nudges at the fragmented shards on the ground with the toe of his slipper. They clink together innocuously. “What was the antecedent event? ‘Cause I told you, that wasn’t me.”

Then what was it? The doc eyes Sans skeptically, plainly suspicious. The insult that Sans’s word is somehow suddenly not good enough would inspire a thrill of irritation if that didn’t require so much effort. He simply meets the doc’s gaze tiredly.

“You don’t think our CTC just triggered its own retrocausal event, do you?”

It isn’t sentient, comes the terse reply. That is quite impossible.

“Okay, but we deal in impossible.” Sans gestures in the vague direction of the doc’s anomaly spectrograph generator with an outflung hand. “Case in point right there, Doc. If it wasn’t our loop or me, what was it?”

I’ll need more time to determine the cause to the effect.

“Well, great.” Sans sighs and props one side of his head up on his hand, as if that might be enough to hold him together. “By all means. I guess we got all the time in the world, huh?”

I do, the doc unhelpfully points out. Temporal status effects appear to have a definitive impact on you; I am quite immune.

“Great,” Sans says again, and slumps back in his seat, folding his arms over the tabletop. “Then you can wake me up when you make some headway.”

A thin hand closes around his bony wrist. The doc’s stare is sharp and unamused.

Do not think this absolves you of helping, however.

“‘Course not,” Sans says, grinning up at the doc with his usual dearth of energy. “Just pulling your leg.”

The doc simply shakes his head, and pushes pencil and paper into Sans’s hands.

Write down everything I say, he instructs. Leave nothing out.

Chapter Text

An empty flask slips from its shelf and smashes on the ground.

Sans stares at it oddly. He’s pretty sure he didn’t do that.

All right, says the doc, excited and feverish. We should be able to make significant progress from here on out.

“That wasn’t - uh, what?” says Sans, puzzled, attention torn between the broken shards of glass and the doc’s seeming non sequitur. “Sorry?”

The paper! The doc clicks his fingers impatiently and, upon Sans’s utterly bemused stare, sighs loudly, a protracted whoosh of air that encapsulates both his weariness and his vexation. You have no idea, do you?

“You, uh, you lost me, Doc.”

The doc turns away, scrambling briefly over the table’s surface, until he produces a pencil and a blank sheet of paper. He turns the paper over and over in his thin fingers, seemingly befuddled. Then his good eye blinks shut in a slow, drained signal of his own self-directed exasperation.

Of course, he says incomprehensibly, to apparently no one in particular, addressing the empty air. I should have known.

Chapter Text

An empty flask slips from its shelf and smashes on the ground.

Sans stares at it oddly. He’s pretty sure he didn’t do that.

Yes, yes, says the doc, beckoning Sans’s attention immediately, that wasn’t you. I know.

“You, uh...what?” says Sans, unnerved at the precision of that guess.

You were about to say that wasn’t you. I know.

“You, um, you pick up some, I dunno, really good predictive skills there, Doc?”

You could say that. The doc kneads at his brow with one knuckled fist, applying generous pressure to the side of his skull. He seems agitated, more than Sans can ever remember him being so before. Come here. I fear I will require your help on this one.

“Uh, all right,” says Sans, pushing himself to his feet with no small amount of effort. “If you say so.”

Chapter Text

“Explain it again?” Sans’s skull has started to ache, a heavy tingling behind both eyesockets that tends to signal an incipient migraine of truly unheard-of proportions.

However tired he feels, it’s probably nothing compared to what the doc’s going through right now, if his story holds any water.

We are caught in a perpetual temporal loop, he says distractedly, the pair of silhouetted levitating hands gesticulating his words so wildly that Sans can barely keep up. He’s standing on a ladder to reach the uppermost part of his blackboard, the only part of the board not utterly obscured in hastily scribbled calculations and chalkdust. After a set timespan of roughly thirty hours, our four-tuple values will reset to the moment that the glass shattered. That is our origin point, for reasons I’ve yet to discern.

“Seems kinda - ”

Far-fetched, absurd, improbable, impossible, confusing, the doc rattles off without missing a beat. I know.


I know because I have heard you say every iteration of those words possible.


As well of every iteration of your reactions to that particular statement.

Sans falls silent, eyeing the doc dubiously.

“So how exactly - ”

We are nearing fifty consecutive loops, the doc says, anticipating Sans’s question with that scarily accurate precision that sends chills running down Sans’s backbone.

“You’re not exaggerating, are you?”

Forty-eight, specifically, as of, he checks the clock mounted on one of the walls, twelve hours in our approximate future.

“Is it really our future if we’re just living the past again?” says Sans with airless indifference.

I have heard that joke thirty times now, the doc says, and it has never once been funny.

“Welp,” says Sans, “I guess that’s what you’d call a temporary solution.”

The piece of chalk snaps in the doc’s hand and lands in two fragments on the floor.

Chapter Text

“So you’re...some kind of antiunitary operator? Is that it?”

My awareness is, at the very least, at this particular point, wholly antilinear.

“All the temporal runoff has - ”

Has built to a point where my current quantum state is poorly-defined, to say in the least. The doc wrenches out a mass of wires from the weblike design of machine spread across the tabletop. Sweat crests his skull, his glasses at an angle askew.

Time reversal operator T’s effects on p exclude effects on x, but if it has effects on p then they wouldn’t be undergoing space-reversal in addition to time-reversal. How does the antiunitary operator exist before the time reversal has even occurred? A CTC is meant to be an unbreakable positive feedback loop, an ongoing ouroboros of sustained energy minus awareness.

It’d be more helpful if this weren’t all purely theoretical. If he could get his hands on the doc’s notes on time dilation...but Sans isn’t the independent vector here, the doc is, and there’s every chance he might have suggested this before. If he suggests it now and he hasn’t suggested it prior to now (in the broader sense; technically there can’t be a before since he’s already existing in both the before and the after in that kind of quantum superstate of dead-alive that’s only meant to exist as a thought experiment), he risks giving away that little secret. He’ll have to figure out a whole new loophole to exploit, and who has time for that, really? The doc’s thorough and clean with all his work, and revealing that Sans has found a channel through space via the by-product of his experimentations is certain to set off an unpleasant chain reaction of consequences.

Or...heh, what’s it matter, anyway? Shouldn’t the doc eventually figure it out? He’s got infinite time to find a solution. In a matter of speaking.

He puts out some feelers for those patches of antispace, the occasional rips in the quantum foam. Usually there’s plenty of them down here, thanks to the doc’s frequent experimentations, but the sheer amount of them is, for some reason, more than a little perplexing.

Can an unresolved CTC provoke an exponential increase in those sorts of aberrations?

Negative space is technically infinite, as opposed to regular old matter, which should not, in theory, be capable of being created or destroyed. But what if it gets swallowed up? What if all of it gets obliterated thanks to an increasing, unsustainable, multiplicative expansion of negative matter until there’s no room for literally anything else?

Well, crap.

“You seem in kind of a hurry,” says Sans. Good thing he’s had so much practice with his poker face.

I’ve told you. Then the doc stops, and sighs, and gives his head a little annoyed shake. No, I haven’t. Not in this particular iteration, but I have told you - the setbacks are spatial in addition to temporal. Mnemonic consistency is the only advantage I have.

Spatiotemporal, then. That could certainly cause an infinite amount of irregularities. A dangerous amount?

Almost certainly.

“So what d’you need me for, anyway?” Sans lets his gaze rove about the room, trying to commit the arrangement of instruments to memory. Funny how he knows it won’t stick. “Presumably everyone’s stuck in the same state that I am. Couldn’t you just call, I dunno, Alphys? She’s better at this kind of thing.”

She is not privy to the same facts that you are.

Ah. This again.

“All about your secrets still, huh?” He catches himself wondering if the doc knows that Sans knows what he knows. Or if the doc knows that Sans knows that the doc knows he knows what he knows.

Or maybe he’s just too distracted.

Sans moves in close, watching the doc work over his shoulder. A trailing wisp of smoke leaks out from the weblike mass of cords and machinery. The doc’s soldering something with the sparking of magic at his bony fingertips, though he’s not entirely clear on what. He’s not the mechanic here. Alphys knows machines back to front. Sans is just the concepts guy. What he does see is a lot of things attached to other things, forming one great winding, snaking interconnected thing with a lot of outlets, a lot of complicated pieces, and a resulting amalgamation of materials roughly the same size and shape as a very large spider.

“So this is the catalyst?”

Correct. The doc’s good eye narrows at the blackish smoke, pinches at one of the wires and gives it a fierce twist.

“Couldn’t you just destroy the catalyst?”

You have suggested this many times, the doc sighs. My answer has always been no. Destruction of my research is nothing short of scientific anathema.

“But destroying the catalyst would break the recurrence, wouldn’t it?”

Something icy coalesces in the pit of his chest. The doc’s stranding them like this. He’s been stranding them like for several renditions of the same song now, and all because, what? Because he can’t bear to destroy his precious research.

I am not trying to break the recurrence. The doc tears himself away from his machine for the first time in Sans’s finitary memory, the corners of his coat flaring, batlike, as he looms. His single good eye skewers him with a blazing, incisive glare, its central pinprick of light all but absent. Sans feels his trademark grin starting to grow brittle at the edges.

I am attempting to prolong it.

Sans's eyesockets go hollow.


If we can go far enough back, reset our values to absolute zero -

“You realize that’s, uh, kinda risky, right?”

Sans stares at him in escalating shock. Has the doc mentioned this before? How should he know? All he can do is take whatever the doc says at face value.

I understand the risks.

“Okay. So you understand the consequences too, then, right? If this falls through?”

To what consequences are you referring?

Sans can’t hold that cutting, one-eyed look, the bladed edge to the doc’s abrupt hand motions. He drops the subject and his stare in the same moment and looks at the floor.



And he means it. Those are the consequences. The consequences are exactly that. Nothing.

"Forget I said anything."

Chapter Text

An empty flask slips from its shelf and smashes on the ground.

Sans stares at it oddly.

Something about the motion seems familiar.

Sans, says the doc tiredly, like he’s issued this very same command a hundred times before, I’d like to be alone now, if you don’t mind.

“Sure,” he says mechanically, withdrawing into the hallway. “Sure thing, Doc.”

He slips outside, makes his way on over to the elevator and settles against the wall of it. The prickle of recollection in his skull is new. He ordinarily wouldn’t think much of it, but, well, hanging with the doc as much as he does has given him a kind of sixth sense for this sort of thing. Stuff that itches at you can’t just be ignored or dismissed as One Of Those Things. It’s never One Of Those Things with the doc. Never.

The doc’s fully absorbed in whatever he’s doing. Perfect opportunity to get away to think. He hits the button that’ll take him closest to the ground floor possible.

The elevator reaches the floor just beneath the ground level - underground level, rather - and Sans shoves his hands into his pockets, rocks back on his heels, and searches out the particular thing he’s looking for.

And stops.

That gives him the same shivering sense that he’s thought that very particular thing before.

This isn’t right.

He’s done this exact thing before, snuck out via his shortcuts, patent pending, and slipped onto the lab’s top floor to snoop around and get his fill of whatever notes the doc keeps from him.

Deja vu’s not an exact science. It never is. But the doc’s in the only room where there’s a machine that can chart stuff like this, which means Sans is going to have to improvise. It’s not like he ever does anything else.

So he takes a shortcut to the room he’s unofficially termed as “his” and nudges the door shut with the toe of his slipper in the same choppy sequence of motions and pulls up the nearest chair.

Cupboard open. Drawers open. He tips all the requisite materials across the tabletop in a protracted scatter of disorganized papers, notes written in halfhearted hands, pens and pencils and compasses and assorted academia. There’s a microscope perched on the far counter, and getting up is overrated. He reaches out a hand, crooks his fingers in just the particular way so he tugs at the curve in space, wraps it in blue, and yanks it into the palm of his hand in one fluid movement.

The doc’s not saying anything, clammed up like he usually is, so Sans will have to take matters into his own hands. He doesn’t like doing that sort of thing, especially since it requires a great deal of effort on his part, but there’s some serious quantum decay eating away at the surrounding fabric here that was already patchy to begin with, some unnerving sequelae for whatever the doc’s doing in his own sectioned-off epicenter of misguided genius. If the doc’s not gonna take responsibility for whatever’s happening, it’s down the Sans to determine the exact etiology of this latest problem.

And it is the doc. He’s reasonably certain of that. He could be wrong, but his intuition is a hardy thing that he’s come to trust, particularly over the last few… He isolates that thought and files it away for later. Doesn’t sound like him.

He breaks the microscope open, cracking its brass exterior sharply over the rounded corner of the metal table, and extricates the highest resolution lens, rolls the fragile thing carefully between thumb and forefinger.

“All right, Doc,” he says with a sharp, satisfied edge to his grin. “Let’s see what you’re hiding, hm?”

There’s a sparking between his fingertips, the blazing spark of blue magic coiling around itself like a magnesium flare.

His work’s not fancy like the doc’s, but if there’s one thing he’s good at, it’s taking shortcuts. The completed result is sloppy, poorly soldered together, fused through the heat generated through the pure ionizing glow of magic, and even the SOUL-shaking blast of an open-jawed skull a few times, for when blue magic just wasn’t producing enough of a heat output to weld the desired materials together.

Sweat’s rolling down his skull in great slippery beads by the time he’s done, but it’s worth it. The clunky bit of machinery built from whatever cannibalized equipment he had on hand swallows up nearly half the room in its sprawling inelegance. Sans’s grin blazes with triumphant exhaustion as he switches it on and starts tracking not the presence of anomalies, but the presence of undisturbed, perfectly normal matter.

He’d been working wholly off a hunch, but the hunch was correct. All those ordinary atoms, the building blocks of their universe, it’s all being funnelled away, and the doc’s right at the center of it. It’s all getting erased, piece by gradual piece.

Sans doesn’t bother with the elevator this time. At this point he hardly has to, there’s so much antimatter clouding the makeup of the lab’s various sublevels. He simply takes a shortcut directly to the doc’s door and, when it doesn’t open to his touch, takes another to take him straight inside.

The room’s crackling with negative energy splayed out in a menacing, latticelike pattern, slipping in and out of the visible spectrum between half-seconds.

Sans barely allows himself the time to take it in. He can’t know entirely what it is, but he knows enough to recognize that it can’t be good.

“You gotta cut this out, Doc,” he says, his tone heavy with warning.

Sans? Surprise flashes briefly in the doc’s single open eye as he spins around to face the unexpected distraction. You shouldn’t -










An empty flask slips from its shelf and smashes on the ground.

Sans blinks.

The laboratory looks the same as it always does. The same it did before…


“Ah,” says Sans, “shit.”

Chapter Text

You’ve retained your memory between events?

“Not until just now, I haven’t,” says Sans heavily. There’s something like twenty-five hours to solve this thing before it all resets again, and he’s starting to get where the doc’s stress might be coming from. They only have the time allotted to make physical progress. If they don’t work quickly enough, it all gets undone by the time the next recurrence rolls around.

Intriguing, says the doc thoughtfully, managing to rip his focus from the problematic variable that is his self-contained time dilation field, how exactly -

“Oh my god, Doc, is now really the time?”

The inflection of annoyance, of frustration, of anything besides Sans’s projected, protracted indolence, is enough to shake the doc out of whatever inimical scientific haze he’s got his brain wound about in.

“So I did a little investigating.” Sans holds up his hands, palms out. The doc’s one-eyed glare is scintillating, and he fixes his eyesockets on a point just beyond the doc’s left shoulder instead. “During the last...loop, process, whatever we’re calling it. Some anomaly-charting of my own, I guess you could say.”

You managed this within the span of a day? He’s not sure if the doc’s tone lands in the realm of impressed or outraged that someone surpassed his technical genius, and he doesn’t pause to examine it.

“No. I didn’t chart anomalies, Doc.”

Ha-ha...oh wow, he’s shaking a bit, isn’t he? This is new. He usually defaults to whatever the doc wants, doesn’t bother offering a contrary opinion because the doc’s extremely good at overriding him and then creating an incredibly complex, detailed chart indicating all the reasons why Sans is wrong and what the doc is right and generally making Sans feel like garbage as a result.

“I charted regular molecular structures. And you know what I found?”

The doc’s hands go still.

“They’re disappearing. Whatever’s going on here? It’s literally eating away at the surrounding space. Doc, what if it spreads?”

Something dangerously close to alarm flashes through that single eye of his. It’s clear at the outset that he hadn’t honestly considered that.

We cannot relinquish our control over this, the doc says at last, grimly. Not yet.

“We’re talking antiparticle increase happening at an exponential level here, Doc.”

And they have no idea if it’s capable of spreading past this central point. The gaps in space have already permeated up to the highest and lowest lab levels, but that’s not accounting for the rest of the Underground or, hell, the rest of the planet. They’re not alone in this. The greater good justification only works if there’s a good that still exists after you’ve mangled the the fabric of the universe, perhaps irreparably.

So yeah. That’s nice.

And we are talking about the future and past of all humans and monsters, the doc counters. Imagine the possibilities if we could seize control of our own linear progression. Imagine what we could -

“Yeah, okay, I’m imagining,” says Sans, doing nothing of the sort, “but right now I’m also imagining a universe where none of us ever existed. This is a violation of every single law possible, Doc, you know that, right?”

Anomalies are by their very nature antithetical, the doc says with a prim twist to the words. This is nothing new.

“Then have you noticed they’re starting to permeate the fabric of where we are, right now?” says Sans with the rising pitch and volume of desperation. “Take a look at the state of things, Doc.”

They’re working the array of spacetime to its absolute breaking point and it’s essentially running an iterative bit-rate reduction on its own atomic structure to compensate. But when the amount of antimatter supersedes the very foundations upon which their universe is built, does that make antimatter the new norm? Does everything else follow?

Sans doesn’t want to complete the thought. They’ve got to make sure it doesn’t come to that.

The doc is silent.

Sans forges ahead. “We need to break the recurrence.”

Absolutely not. The doc’s tone is adamant. We cannot possibly sacrifice this.

“I get where you’re coming from, Doc.” Sans runs a hand over the back of his skull, rubbing at the cervical vertebrae nervously. “Really, I do. You’ve done something incredible, all right?”

The rare compliment is enough to give the doc pause, keep him from turning back to his work with a snort of indifference that’s more than typical for him.

“But we can’t afford to sacrifice everyone’s existence for this one thing. You get that? We don’t have that right.”

Of course we do, says the doc.

“Wh - ” Sans feels the lights in his eyesockets wink out. “Doc, what’re y - no, no, we - we don’t.”

For the future of the entirety of monsterkind? The doc’s eye is doing that forbidding flaring thing where the ridge of the socket curves downward and the light sparks with an eerie intensity that seems to drain all other sources of light from the room. Yes. We absolutely do.

“Have you forgotten the basic purpose of a cost/benefits analysis?” Sans says weakly. His kneecaps are starting to wobble, a little bit. He feels like he might need to sit down. He feels like, if he had blood, it’d all be going to his head and making him feel all light and dizzy. Funny thing, he kind of already does feel light and dizzy. That’s an interesting reaction.

My job is to ensure that monsterkind does not remain trapped down here, the doc says sharply. I will accomplish that task at any cost.

Sans stares at him, two tired specks of light locked on the doc’s single blazing one.

He abruptly yanks himself back from the precipice he’s been teetering on the edge of. The precipice of doing something he might regret, that both of them might regret, and since his antilinearity has been pretty damn well established at this point, he can no longer cite mnemonic inconsistency as an excuse. Has he in the past? You know, he really can’t remember. His recurrent memory only stretches back so far if he really jogs his thoughts.

“We don’t know how long this is going to be sustainable,” he says at last.

Then we work until the last minute, says the doc, his movements curt and venomous.

Sans thinks he might have made a joke about how little time measurements matter in these circumstances. Or a previous iteration of him might have. Did he stop existing between each reestablishment to the origin point?

He recognizes the compromise for the closest thing to an agreement they’re likely to get.

If all else fails, he’ll break the recurrence himself.

Sans sighs.


Chapter Text

“You know the thing about irrational numbers?”

What? sighs the doc.

“You should despise them,” says Sans with a wide smirk.

You are insufferable, says the doc with the arid drape of sarcasm over a poorly-concealed fondness.

“Right back atcha, Doc,” says Sans, winking tiredly. “You know it’s all derivative.”

The doc briefly buries his face in his hands and makes a sound very similar to a dry hiccup of laughter.

Chapter Text

That isn’t good enough, the doc snaps.

“Well, then what is?” says Sans. His skull aches. Everything aches.

I am attempting to push the origin point back, Sans, not forward.

“How far back are we talking, here?”

Before the barrier was set in place. Before monsters were trapped.

“Doc, I don’t - I’m not sure that’s such a good idea. We’re stretching the limits of what should be possible as it is - ”

If we don’t, this entire thought experiment will have been for nothing.

“Thought experiment? This is for real, Doc, c’mon.”

You think this sort of thing is reproducible?

“I think it’s way too reproducible,” says Sans with a faint chuckle that just seems spectacularly rote at this point.

You’re not funny, says the doc, and this time he means it.

Sans doesn’t make the joke again.

Chapter Text

“You should eat,” says Sans.

Later, says the doc dismissively.

“You’ve been running on fumes as it is, Doc, and how many recurrences have you gone without eating now? Five? Six?”

The doc closes his eye. Ten.

“Eh. Close enough.”

Sans shoves the package of noodles towards him, and it skids across the table with the crackle of plastic packaging over metal. The doc eyes them as if they’re a particularly slimy foreign specimen.

“Alphys won’t miss them,” Sans says amiably. “Especially not if we don’t solve this before the next windback.”

It makes little difference, says the doc coldly. By the time our CTC reactivates, I will have never eaten again.

“Don’t underestimate the value of good food, Doc,” says Sans, tapping the side of his skull with a finger.

This is not good food.

“Then don’t underestimate the value of eating. You need the energy, all right?”

Since when have you elected yourself my caretaker?

“Since you stopped caring enough to feed yourself.”

I’ve no idea what you -

“Doc,” says Sans, the grin frozen on his face, a drained, trembling facsimile over his own crushing fatigue, “just eat the damn noodles.”

The doc blinks, then rips the package open with a grunt of assent.

Chapter Text

“We’re not getting anywhere,” Sans says heavily, “are we?”

The doc pinches at the spot between his eyes with his thumb and forefinger, head bowed.

Time has shredded the lab’s lower levels beyond almost all recognition. Corners of tabletops and scuffed metal counters fade and flicker between nanoseconds, as if any moment the fractured edge of nonexistence might rip them all away and render them utterly beyond retrieval. In fact - how many levels are there to these labs? How many were there, will there be? Sans felt that it might have once landed in the double digits. Now he’s not so sure. Even his mnemonic retention has its limits, apparently.

“Let’s face it, Doc,” says Sans, “we can’t reassign our t0 because we’re both caught in the t0 - t1 feedback. We can’t affect the variables while we are some of those variables.”

It must be possible, the doc snarls back, a cold spike of irritation in the face of improbability.

“We can reproduce this, all right?” The break in his voice gives way to a lurching desperation, the corners of his grin trembling indicatively. “We can set the t0 value on our own terms, all right? Right now, we’re just going in circles. And if we go any further - ”

I will not give this up! snaps the doc, and for the first time in Sans’s memory, his composure doesn’t simply slip but drops utterly, shed like a secondary skin, as the doc draws himself to his full stature, unbowed, and skewers Sans with a penetrating, furious look. I will cut us free of this wretched state. I will save the future of monsterkind by ensuring we are never trapped down here in the first place.

“This isn’t the way, Doc,” says Sans, but the doc surges over him easily.

I don’t even know if this is reproducible.

Sans’s grin freezes on the spot, the lights in his eyesockets shrinking into infinitesimal dots.

“What,” he says flatly.

I don’t - The doc breaks it off, looks away, and abruptly he’s the same withdrawn genius he always is, his calm efficiency secure and intact. I don’t think I can reproduce this. This is the closest I have ever gotten. Ever will get.


The doc, the brilliant, self-absorbed genius who has no conception of his own limits and no recognition of his own flaws, just admitted that he isn’t invincible. That he isn’t infallible. That he has his limitations and restrictions, and that he can honestly and truly go no further.

The level of psychological duress he must be under to admit such a thing must be beyond anything Sans has seen before.

“This isn’t the way, Doc,” he says quietly. “Please. Let’s just stop this now.”

Before they lose everything. Before they lose everything and not even know how much they’ve lost. They could have lost innumerable things already, not just in the physical sense, but in the physiological, in the internal, in the cognitive. They might not even be the same monsters they were at this point.

The Royal Scientist, that unshakable solid point, the monster willing to become so refracted and distorted by his own inability to admit defeat that he would rather sacrifice the entirety of his and everyone else’s collective consciousness than succumb to his failure.

Was he always like that?

There’s no way to really tell, is there? Fragments of them have already been lost, in all likelihood, irretrievable, and Sans tries not to let the thought ensnarl him in a wave of existential dread.

The doc wavers. Sans doesn’t dare say anything for fear that it might tip him one way or another.

His features crystalize into a defiant sneer.

No, the doc says. Never.

Chapter Text

Sans sighs and rearranges himself so that the curvature of his spine is pretty well neatly aligned on a horizontal plane, which gives him a very clear view of the ceiling with its weird cement-rock compound, gray with the sickly verdigris of neglect. He wonders if the accumulation of dust across several consecutive recurrences would be the same every time. Does their presence affect the accumulation of dust motes across the many tabletops and chairs and floors in the lower levels? Ostensibly it would, given the physics of air traction and air resistance and gravity.


Sans snaps his fingers. The shattered remains of the flask that’s stir feebly on the ground, ensconced in fading blue light.

“What if we altered the origin point?” he comments to the ceiling.

The ceiling has no reply.

That is what I am attempting to do, yes, the doc says acerbically.

“I mean, what if we prevented the glass from breaking at all?”

He swirls the array of shattered pieces with the crook of a fingertip. They do little besides clink together forlornly.

The broken flask is not the catalyst of our origin point, says the doc, exasperated, merely the effect of it.

“So what was the cause?” asks Sans. “Did you ever get that far?”

That is not my primary focus.

“You want to extend our t0 point to before the glass falls,” says Sans. “Shouldn’t that maybe be your focus? Since we can’t determine what caused it in the first place?”

So, yeah, there’s some kind of retrocausal trigger happening here, he’s pretty sure. Now that his memory retention is more or less at its one hundred percent capacity, he has a better idea of how things transition between recurrent loops. That is to say, extremely choppily, without any kind of graceful segue whatsoever.

God but causal violations are the worst.

The doc makes an irritated sound that rasps at the back of his throat, the closest approximation to a spoken word coming from him that Sans has ever heard, like admitting that Sans might have a point is an actual tremendously painful experience for him, which Sans is too tired to comment upon but finds vaguely offensive on three levels: 1) he has made plenty of good points in plenty of past happenstances, and he might not be able to drag up any specific references, but he’s absolutely certain that he has; 2) the doc is an awful mix of irrepressibly frustrating and insufferably self-assured, and never wants to admit anything to anyone through no fault of anyone else, and he could have trouble admitting to the laws of thermodynamics if someone else proposed them before he discovered them himself; and 3) whatever.

The doc wants to shred the fabric of space, time, and spacetime for the sake of his own vainglorious endgame, fine. When does it matter to a skeleton he doesn’t even dare to confide in half the time? Sans shuts his eyesockets and tries not to feel the way he does, a sullen, abandoned, tired thing lying emptily on the floor of a lab that shouldn’t exist and may progress to the point of self-erasure if someone doesn’t contain the temporal recurrence that’s ensnared it in a self-perpetuating loop of destructive intent. The lab’s going to wipe itself clean, and they’ll be taken with it. The doc will persist to his own end, because that’s the sort of man he is, the man who speaks in hands, the man with the flair of the self-important and dramatic and mysterious and reclusive, who puts far too much work into maintaining that aura for someone who pretends not to care what other people think of him, the man who took Sans’s hand and told him to run and hauled him along through the gaps while everything else crumbled, who told him they would have to continue and endure and in that moment that had been the worst thing, the worst possible thing he could have told Sans because he’d known the doc, not personally, not deeply, not well, but he’d known him and god he wanted to be him, he wanted to be the man who spoke in hands and drifted from place to place like an eidolic arbiter of profound academia, the man who discovered how to cut through the scattered web of spatial molecules like a hot knife through butter and cleave oneself straight into another world. Because that’s who he is. The man who backs himself into so many corners that he has no other options but to rend himself apart to claw his way out of them. Who destroys himself, remakes himself, is willing destroy himself and remake himself again and again and again and again and again, but Sans -

It strikes Sans that the doc can hew himself in two all he wants; Sans - Sans can’t. Or he can, but he thinks of Alphys, of her blazingly enthusiastic slew of technological babble and her delight at a new potential breakthrough, of the groups of monsters he’s never met, whose salvation he’s been silently working towards, who are unaware of the paradox building in the center of a lab none of them have been to that has all the brisance of an incipient explosion.

He’ll never be who the doc is.

He’ll never be the man who ruthlessly deviates from his own morality and aspires to self-erasure so potently and sorely and bitterly that he’ll risk the destruction of all existing matter just to prove himself right.

Sans gets up.

His bones react slowly, leaden with the weight of gravity and with what he’s about to do, as if the air density sensed his intent and abruptly shifted its viscosity to make it that much more difficult for him.

“We’re ending it,” he says heavily.

Pardon? says the doc, not listening, like he always does.

“We’re stopping this before the next recurrence, Doc.” Sans stares at the doc’s tall, sloping back without seeing it, the ink-black of his coat draped about him like a curtain torn. “We have to.”

Don’t be absurd.

Sans’s head is light again, pulsing with the vague sense of unreality as it seeps into his marrow, a creeping inflorescence of the things he can’t admit or explain.

“Please, Doc,” he says. The word splits cleanly down the middle. “We’ve gotta stop this. We’ll try again, I promise. But right now - right now we’re risking too much. Costs and benefits, remember?”

The doc stops.

Costs and benefits, he says thoughtfully, to the empty air in front of him.

He moves so swiftly Sans has room for nothing but a startled flinch before the doc’s thin hand flies out, prompting the searing blast of white-hot energy from a pair of gaping jaws that reduces his bones to ash.

Chapter Text

An empty flask slips from its shelf and smashes on the ground.

Sans runs a trembling hand over the ribs of his chest, over the ridges of his skull, blinking rapidly. He can’t count the moments between the ensuing agony of getting a unidirectional surge of energy straight to the whole of him and the instant that his eyes opened again and he ended up back here. Here, in a lab strewn with all manner of tools and miscellany, the backdrop of bleak, faded green whose precise shade he is beginning to hate.



For a certain value of “alive”.

That value being “nominally”.

It appears death would be impermanent in these circumstances, the doc comments icily. Still. Still he doesn’t bother to so much as glance up. Curious.

So. That’s all that was to him. A drawback. More time wasted. A stimulating mental exercise.

He took the slender hand when it was offered to him, because he wanted to be him, the doc with all his detached mystery and isolation. He took it the hand and fled and lived and he owes everything, everything that he is to this tall, stubborn, overly analytical monster who just incinerated him without a second thought, for the crime of being in his way. Because he was willing to unmake something that would unmake the space they’re occupying and perhaps more with the scintillating intensity of a star gone supernova. Except instead of light and matter, there would be the lack thereof. An empty void where monsterkind once resided. Where any kind of life once resided.

For a long moment, he can’t muster anything to say to that.

“That was pretty low, Doc.”

Sans almost doesn’t recognize the voice as his own. It’s joking, jovial, but there’s an undercurrent to it, that coiled menace redolent of an incipient threat. The doc’s been trying his limits since this whole mess started, and he just hit the absolute nadir of Sans’s tolerance for it.

The doc’s not perfect. He knows that. Anyone who presses the limits of existence simply because he can, because of his own curiosity or intrigue or stunted morals, that’s not right, that’s not justified by any stretch of the imagination but standing up to the doc’s positively eclipsing personality was always more effort than it was worth. Particularly since, as the doc never hesitates to remind him - Sans owes him.

I am going to save all of monsterkind from complete catastrophe.

“You’re gonna risk fracturing the entire timeline for the sake of proving your theories right.”

...huh. Wow. This is peculiar. He feels...angry.

Never felt that one before. It’s kind of exhilarating. ‘Course, it’s gonna tire him out even quicker, but if they’re due for a scaleback eventually, what’s the point, right? He can get mad. It feels weirdly refreshing, honestly. No more bottling it all up.

Especially if the doc is feeling trigger-happy.


What a punchline, right folks?

“And you just killed me to do it.”

You would have put an end to it, says the doc crisply. And that is not your call.

“It is when it’s rupturing the entirety of spacetime,” says Sans. “You can’t just make these - unilateral decisions that could affect literally everything, all right? If you’re not gonna stop it, I will.”

That’s really how you feel about it? says the doc, intrigued, like this is some kind of mild distraction, potentially interesting, improbably unsatisfying.

“You think I can’t see it?” Surely the doc can see it - surely he can. The ripples of each closed timelike curve once it bends back on itself like the circuitous, topological hell it is, they’re leaving more than residual scars on the way things should be. They’re tearing it all apart, like an impossibly bright light cutting through fragile bone. Like...hah.

“Hang on - Doc, can you see it?” His grin slips, if only for a second, eyesockets going dead and empty with shock at the concept.

Of course I can, snaps the doc with the taut xeric pull of unmistakable envy.

Envy, like someone who’s putting up that front, that façade of uncaring. Enigmatic guy, sure, but when you’ve spent as much time around someone as Sans has - he has to laugh hollowly at that joke, because isn’t it just so damned true - certain tells start to leak through the chinks in his armor. Not impervious. Not all-knowing. Not absolved of all guilt or grief or blame for whatever might come next, or from whatever might have already happened.

Neither of them are.

The lights in his eyesockets hum back, faint speckles of white as the ridges over them knit down. He feels like, in any other circumstances, he’d be springing for smug right about now. As it is, he can only go for amazed.

“You can’t, can you?”

I’ve no time for this. With an darkly familiar flick of one wrist, one of those massive skulls materializes, eyes gleaming with supercharged plasmic energy.

“Doc - ” says Sans.

I’m sorry, Sans, the doc says dispassionately.

He leaves no room for Sans to escape the startlingly wide radius of the blast.

Chapter Text

An empty flask slips from its shelf and smashes on the ground.

Sans stands across from the doc tiredly, hands in pockets, eyelids drooping, watching the doc pretend not to watch him from the corner of his good eye. Distracted.

The doc hates distractions.

Sans sighs.

“I’m not gonna convince you otherwise, am I?” says Sans.

No, says the doc, and executes him with a punctilious burst of scalding, ionizing, thermal energy.

Chapter Text

An empty flask slips from its shelf and smashes on the ground.

“Cut it out, Doc.”

This time Sans dives across the table in time to watch the skull discharge a hot gush energy into the wall and punch a hole clean through it. The doc looks furious only for a moment before he gestures again, harsh and fierce, and two more of the things manifest, above and and to the right of him.

No evading it, even with the tiny square of space available for him to leap toward to dodge the cross of white bars slicing across his vision. They cut through him effortlessly.

He lets them.

An empty flask slips from its shelf and smashes on the ground.

Sans makes it halfway around the table before the doc skewers him through with a line of femurs. He’d make a joke about the inelegance of such a murder if his eyes hadn’t gone dead and his SOUL splintered into pieces among pieces. The doc’s fingers brush against the fragments instants before they decoalesce into nothing.

Curious. Too bad the SOUL of a monster doesn’t last long enough to key into any of the doc’s plans.

An empty flask slips from its shelf and smashes on the ground.

He cuts straight for the door and gets a leering skull in his face for the trouble. No escaping it once you’re pinned against the wall.

An empty flask slips from its shelf and smashes on the ground.

He clears a line of bones as the doc slings them at him, one after another, an unbroken string of ulnas fencing him in while the great blasters hovering overhead do the rest.

Sans doesn’t stand a chance. He lets it happen.

An empty flask slips from its shelf and smashes on the ground.

Sans raises his hands in tired surrender.

The doc hits him with several consecutive blasts with the wave of a hand as if batting away a particularly bothersome gnat.

An empty flask slips from its shelf and smashes on the ground.

“I get the point,” says Sans.

Or he would have said it, if he hadn’t taken a step forward and immediately been tripped into a sharpened line of radiuses.

An empty flask slips from its shelf and smashes on the ground.

He doesn’t move. The doc doesn’t take any chances, and disintegrates him anyway.

An empty flask slips from its shelf and smashes on the ground.

Sans puts his head in his hands for the split second he gets before it all goes to hell.

An empty flask slips from its shelf and smashes on the ground.

Sans tells the doc to stop, please, he gets it.

An empty flask slips from its shelf and smashes on the ground.

Sans tells the doc that dying really, really hurts because he can remember each time it happens.

An empty flask slips from its shelf and smashes on the ground.

Sans tells the doc that he’s made his point.

An empty flask slips from its shelf and smashes on the ground.

Sans tells the doc that he swears he won’t say another word, won’t get in the way, won’t do anything, just please, please just stop -

He doesn’t get any farther.

An empty flask slips from its shelf and smashes on the ground.

“I’m sorry,” says Sans.

An empty flask slips from its shelf and smashes on the ground.

“I’m sorry,” says Sans.

An empty flask slips from its shelf and smashes on the ground.

“Stop it,” says Sans.

An empty flask slips from its shelf and smashes on the ground.

”Stop it,” says Sans.

An empty flask slips from its shelf and smashes on the ground.

“Cut it out,” says Sans. And he reaches out into the bright curve of space with his left hand without fully grasping what it is he’s doing, sinks fingertips into the far-too-frequent grooves where the patchy antispace floats, smooth and slippery, and works his fingerboness around a particular edge and pulls and something gives to it, something cedes to the impulse and materializes behind him in a flare of solidifying matter, an open-jawed skull with its maw gaping emptily, its eyes alight with a feverish spark, and he doesn’t know how he manages it and he doesn’t care because there’s more antimatter in this laboratory than there is matter at this point so it’s all moot at any rate. He doesn’t care. He doesn’t care. He closes his hand into a fist and the skull yields to him, hurling forth an impossibly superheated wave of condensed energy and slicing through the remaining spatial matter, hewing legs off the metal table so all the instruments slide from the surface with the harsh tinny screech of steel over steel. And it doesn’t even matter, it doesn’t even matter, it doesn’t even matter because they always cut back to the glass hitting the floor and even if he puts up a fight the doc’ll inevitably get the upper hand, he always does, he’s better at this and he’s been doing it a lot longer than Sans ever has and likely ever will, he of the fluxing height and silver-speckled coat and single dark, glaring eye and stern face, permanently unfrozen in the opposite of the typical skeleton’s ever-present rictus. Because he’s the doc, he’s untouchable, invincible, and Sans is just Sans. He’ll talk back and he’ll apologize and he’ll do whatever he has to if it’ll sweep this all underneath the table, the table that’s collapsed on itself by now, whoops, and this will all get wiped back anyway so what, he has to ask, what is the point in even trying.

The point is that he’s sick of the doc executing him without a second thought, simply eliminating him like a disagreeable pet or an incomplete function. And he’s tired. He’s - he’s really damn tired. The point is that the world is rending itself apart under the pressure of the doc’s impossible, risky attempts to strain the world’s quantum-physical restrictions, and if Sans is the only person with the awareness and wherewithal to stop it before things escalate any further, then he’ll have to be the monster to do it, won’t he? There’s no other choice. There’s no other option. Infinite time only gives the illusion of choice, but they’re on a finite timer here and there’s only so many end results for p1 in a CTC like this one, and they’ve all but exhausted the possibilities. It’s time to throw in the towel. It’s been time to throw in the towel for a long time now, if only the doc weren’t so damned persistent. Just a little further, just to see how far it’ll go, he must think.

The drone of that isothermic, fluctuating pillar of searing light sluicing through walls and counters and tables and chairs without discrimination is practically the illusion of victory, and Sans turns the thing around on the doc, who watches him, alarmed and perhaps even a little bit scared.

Too bad his damage output is pathetic, utterly untested, barely scraping the top off the doc’s ramrod-taut posture. Single-digit variables, unchanging, a critical failure in even the most charitable of evaluations. Sweat streams from his skull. Eyes hollow.

The doc surrounds him in a circle of the things, and fires them all off simultaneously. Sans never had a chance.

An empty flask slips from its shelf and smashes on the ground.

Sans takes a shortcut out of the lab, and takes another to the highest level he can, the level the doc doesn’t know he knows how to access, and another, and another, and another. He keeps cutting through every instance of non-anomalous spatial matter he runs into until there’s nothing left to slip out and away from, and then he leans against the wall and clutches his chest where his heart isn’t beating, sweat rolling down his skull in thick, viscous drops.

With any luck, if luck weren’t such a nonexistent, unstable factor, the doc won’t know how to follow him. Maybe he’ll track him down. Or maybe he’ll decide the work is more important than burning out a potential obstruction.

In any case, it’s time to evaluate the options.

The doc is...the doc is a problem. It’s taken him longer than he cares to think to admit it. The doc’s a problem, a problem surrounded by too many stochastic variables, all the diverging splotches of hemorrhaging spacetime that he’s honestly not sure how to fix, if a problem like that even is fixable. Winding them through recurrence after recurrence, redivivus, as if patching one’s t0 value were as simple in practice as it would be in theory. The theoretical has nothing on the starkly practical, particularly since the physical is, technically speaking, not awfully long for this world at this rate.

The doc’s notes. He’s got access to them - limited access, maybe, but if the doc’s played his hand then it’s only fair that Sans play his. He makes a beeline for the stacks of papers written in hands, rifles through them feverishly, turning aside one after another, discarding them all until they’re nothing more than a cairn of crackling conceptual possibilities. He treads on them as he turns away, running a hand over the smooth planar surface of his skull, smile straining, sweat sliding off the edges. The doc thinks too big. Thinks his limits are farther than they are, thinks he can stretch himself onward forever. No conceptualization of his own restrictions. Maybe Sans’s problem is that he never thought big enough, but not thinking big enough is safer. Less liable to get you or everyone else killed.

He casts a desperate look toward the door to the rest of the Underground, still sealed shut. There’s more than enough antiparticles crowding the area here for him to slip out unnoticed, in theory. Obtain that wistful freedom, if only for a limited time, an ultimately pointless effort. But it would be the principle of the thing, the concept of breaking those rules and limitations, the knowing of what he could and can do without the doc’s instruction. He stretches a hand for the door.

He snatches it back.

Temporal runoff.

He’s a threat now too. If he wasn’t before, he sure as hell is now.

He looks to the computer perched on one of the desk’s, festooned with a cluster of glittery stickers and obscure references. Alphys’s, no doubt. A memory of messing around with her internal files prickles at the corner of his mind, but who knows the amount of time that’s passed since then - in a manner of speaking. Another effort rendered pointless by the doc’s efforts, even unintentionally.

But it gives him an idea.

There’s only one number in his phone. He dials it. It takes three rings for someone to pick up, and there’s a lengthy pause before there’s an answer.

“H-hey, Sans!”

“Alphys. Hey. Listen, I kinda got something of an emergency.”

“A-an emergency? Wh-wh-what kind of, um…?”

Crap. Okay. Wrong approach. He really should’ve known better, huh. He revises whatever he was about to say and chuckles in what he hopes comes across as an appropriately disarming way, hand in pocket. Sans, what a joker. What a comic.

“Hypothetical emergency.”

“Oh!” Well, that clears things up. “Um, how can I, um...should I, should I come in? Do you need me to - ?”

“Nah, nothing like that. I just gotta ask if you know anything about time dilation.”

“T-time dilation?” Her voice leaps several octaves until it’s little more than a stuttering squeak. ”Wh-what are you, uhhh…?”

“Y’know, antichronologic loops and all that.” He leans against the counter. The clock’s hands tick slow and steady, but he’d swear they’re moving faster. The doors are closed. Nothing’s snaked out to find him here. The doc doesn’t even know he knows his way here. Unless he already told him some other time but, well, Sans isn’t thinking about that. “I’m talkin’ a state of perpetual hysteresis, endless recurrence. Say there was a machine that generated that kind of thing on a mass, all-encompassing scale.”

“H-hold on.” The audio feed momentarily cuts out, drowned by the rustling of blueprints being drawn close, the scratches of pencil to crackling paper.

See, this is what he loves about Alphys. He’s just gotta drop a few key concepts and she’s right on the same page, doesn’t even need to ask questions. Her love of the problem will pull her through to the other side, however little she might think of her capabilities. This kinda tech is completely outta his purview, and it’s not like the doc’s talking.

“No limitations?” she pauses in her musings to ask.

“Mm-mm,” he hums to the negative. “Mechanical catalyst. Just like your basic theoretical t1(c(t1 - t0)) loop, rigid variables. No awareness to the state of things, unless you’re near the center of the dilation field. Kinda like the eye in a hurricane, you know.”

“Is that even possible?” Again Alphys hesitates. Sans rubs a fingerbone over his nasal bridge and shuts his eyesockets.

“I gotta theory. I just gotta know - if that sorta thing is mechanically generated, supposedly infinitary, would breaking the technical catalyst resolve it?”

“W-well, um…” The scuffling of graphite on paper resumes. “It’s a bit, um, a bit more complicated than that. To sustain a period of antichronologic hysteresis, y-you’d need to generate a lot of power. Like, um, we’re talking CORE levels here.”

Something in Sans’s chest constricts.

‘Course, he’d been hoping for something a little simpler.

“CORE levels? It’s - it’s not a very lengthy recurrence. I mean, in terms of the time period, it can’t be longer than thirty hours, give or take.”

“But, um, it’s still an ongoing p-positive feedback loop, right? S-so it’s gotta be powered by s-something that can sustain it indefinitely. And I-I mean, destroying that ‘catalyst,’ you called it? That might break the cycle, b-but, um, it also might, might, er, end up d-detonating whatever’s being use to power it?”

No, no, that makes sense. She’s right. Of course she’s right. He hadn’t stopped to consider the requisite power that one would have to catalyze a situation like this. He’s not even sure if the doc knows. Would the doc examine the etiology of something if it managed to accomplish what he wanted it to? In this case, no, probably not. Not when he’s so bent on rearranging their t0 values to the exclusion of all else.

So. Short of jacking that little recurrence output-generator directly in the CORE, what could possibly generate that level of power that could fuel -

Sans feels his grin set, the dots of light sparking out and leaving him dead hollow.

The doc’s got plenty of power. Three SOULs’ worth of it, to be exact.


“So, um,” says Alphys, blissfully oblivious to the horrible blip of nightmarish realization drumming away in Sans’s cranium, “wh-what kind of setup would we be looking at? Your free field is identical to zero, r-right?”

“Not for much longer,” says Sans.


“Nothing,” says Sans, turning on his heel. “Look, I gotta go. The doc’s getting real antsy, and you know how he is.”

“Um - ”

“I’ll talk to you later.”

“What d-do you - ”

He hangs up before she can ask whatever it is she was about to ask. He reindexes f values 1.43101 on the (x/65.7090004) slope so the phone zooms along its Y-axis and thuds dully against the opposite wall.

He’d mentally apologize, but there’s a tired phrase in his head about points and pointlessness. The long and short of it is that he can’t afford distractions at this juncture.

He makes a list of what he’s got on his side. Minimal damage output. Wresting control away from the doc long enough to seize one of those powered-up weapons of his, but without the sculpted intent behind it, the effort will be wasted. Maybe hating him would make this easier, make his attempts to stymie the doc more potent. But hatred - hatred requires anger, and anger sounds like work. If he just sat back like the doc wants, just let it happen, it would all fade out anyway. No more monsters. Possibly no more reality, either, but there’s kind of a glacial poetry to that. The humans getting eaten alive by their own universe, and all because they sealed monsterkind underground. There’d be a vicious, vindictive satisfaction in that. He hates himself for entertaining the thought.

The clock’s ticking, and he’s running out of time. Figuratively. Literally, he’s got way more time than anyone should ever know what to do with, the doc included. He’s the only variable with the potentiality to divert from the p1 destination and trim the tautology at the source, before everything torques and twists and unravels in heated brisance, tearing the quantum foam apart at the seams. That’s way more pressure than is suited for one squat skeleton with a weakness for virtually everything. All it ever takes is one wrong step, one twisted anklebone, and then he trips and faceplants and then what happens? No one else is gonna get to stick around here to annoy the doc with hilarious puns.

The doc’s gonna kill him, probably. Or come damn close to it, but there’s the whole risks versus rewards thing, costs and benefits, and besides, who’d want to live their whole life in the same recurring, unstable structure, anyway? Would lend a whole new meaning to the word “bored out of your skull,” right?

Sans’s grin widens, hot and brittle. Here we go.

Better to go out with a smile.

Chapter Text

An empty flask slips from its shelf and smashes on the ground.

The doc raises a hand, and Sans can see the arc of the blast before it happens, because every time it happens it happens just so, and the skull gapes and fires, he’s no longer there to weather the surge of white-hot energy.


“Sorry, Doc,” says Sans, not sorry at all. There’s a flash of startled outrage over the doc’s indistinct features before he winds back again, unleashes a circle of the things, coiling around and around him, wholly inescapable.

Well, perhaps not “wholly”. Sans takes a shortcut and ends up outside the radius of the blast.

Stand still, snaps the doc.

“I’m sorry,” says Sans. The doc fires again, misses.

Fires again.


“I’m real sorry,” says Sans.

The doc hurls a gauntlet of femurs, carving through ground at Sans from both sides, and he takes another shortcut and ends up on the table, out of their reach.

“I wouldn’t do this if I felt like there was any other choice,” says Sans.

The smile’s starting to hurt.

The doc shoots three consecutive pillars of bright heat, and Sans leaps to the empty space behind them.

“I wouldn’t do this at all, really,” says Sans.

The hot, thick stench of magic pours from the doc’s hands as they open, shooting startlingly white bones like bullets. He waits until the absolute last moment, the hail of sharpened marrow cutting through the fracturing space, then scoots out of the way, ends up at the doc’s elbow.

“You know how I feel about work,” says Sans.

The doc spins, furious, his hands cutting like hot knives through the air.

Sans reaches out, the sweat thick and glistening, and seizes at the scrap of space that should be what he’s shooting for. He brushes it with knucklebones, smoothing it out, and -

And the doc stops him with a clean, severing gesture across his chest.

You think you could exert an independent gravitational pull on me? He sounds apoplectic, single eye blazing.

Ah. Whoops.

You cannot be serious.

“You know me, Doc.” Sans grins, weakly. “I’m always dead serious.”

The doc seems to expand, the black edges of his coat rippling outward like dark matter, an unearthly sound like a dial tone screeching through the murk.

An empty flask slips from its shelf and smashes on the ground.

Stay still, the doc commands, turning on his heel to deal Sans a stinging backhand.

It misses. Sans practically has to dance backward to make it happen, but it does.

How are you - the doc begins, incensed.

Sans taps the side of his skull.

“Anticipation. Funny how dying a hundred times over does that to you.”

He chuckles. There’s no mirth to it.

The doc executes the same circular maneuver as before, attempting to surround a skeleton that slips out of the loop - a loophole, if one will - before it closes.

I do not miss! The doc actually sounds - well, he actually sounds mad. Wow. That’s a new one. Looks like they’re all discovering new and exciting things about each other today.

“You do now,” says Sans with a cheerful wink. And backs himself right up into a wall, his heel striking concrete with a loud click. Nowhere left to go. A line of bones springs up and skewers him on the spot.

An empty flask slips from its shelf and smashes on the ground.

“Welp,” Sans says, “guess I learned my lesson from that one.”

The next blast nearly obliterates him on the spot, and the one riding the fading streak of white, lined up the tiniest bit to the left, that one definitely does.

An empty flask slips from its shelf and smashes on the ground.

The grin’s as hollow as he is when he looks the doc straight in the eye and cocks his skull.

“Don’t make it easy, now.”

The doc stares at him in disgust, in confusion, in morphing outrage. This time Sans cuts directly to the chase. The first onslaught nearly wipes him off the temporal map, but he clips straight for the delicate filigree of machinery on the table and launches a flurry of shinbones through it.

If he had breath, he’d hold it. The doc makes an outraged sound, and Sans doesn’t get the chance to dodge the next searing roar of energy, so he lets it happen.

An empty flask slips from its shelf and smashes on the ground.

“But I destroyed the catalyst,” says Sans, straining to glimpse the apparatus on the table. It’s still sprawled there, silver, spindly, wholly intact.

Alphys was right.

The doc vaporizes him in another wave of thermal agony.

An empty flask slips from its shelf and smashes on the ground.

It’s a steep learning curve, is what it is. Every scaleback to the anchor point gives him more time, in a manner of speaking, but they’re dancing on the edge of existence here, and even if Sans were a gambler (he isn’t), those aren’t great odds he’s playing against. The doc’s learning too, with every restart of their miniature, warped CTC. He’s learning Sans’s tricks and games, and the anticipatory jerk of a hand preempts any attempt Sans might make to slide out of the way of a singeing, surging blast.

So. Back to his main thought before he was, uh, unceremoniously offed by his former friend-cum-mentor, now neither of those things. Alphys was right. Destruction of the catalyst isn’t the only necessary step, even if the doc clearly didn’t take the ruination of his work very lightly. His firm, tight expression has calcified into one of rage and frustration as he endeavors, again and again, to swat away the gadfly of a skeleton that’s interfering with his treasured creation. He’s not powering the thing on SOULs, either, or there’d be one in the room too - no, those are far too valuable to exploit like this. Or maybe the doc simply hasn’t thought of that yet.

Doesn’t matter.

“I’m starting to get the feeling,” Sans says idly, ducking a bright wave of armbones as they come sailing overhead, cutting through the ceiling effortlessly, “that you might have some kind of bone to pick with me.”

Shut up, the doc snarls.

“Look, you know I respect you, Doc. I do, truly.” He gets a hand to his chest, roughly in the position where a heart would be if he had any need for such an organ. “But we’ve reached the end. Soon, there’s gonna be nothing left to save.”

SHUT UP. The doc practically screams it, one hand jerking up roughly. There’s a quiet, heavy ping of Sans’s SOUL jerking oddly in his chest -

He slams into the ground, and a row of sharpened rows spikes up to greet him.

An empty flask slips from its shelf and smashes on the ground.

Sans grimances. So that’s what it feels like.

Well, getting that vicious injection of increased gravity straight to the SOUL never did look like it’d be pleasant.

“You turned me blue?” he says, indignant disbelief leaching into his tone despite himself. “Really, Doc?”

The doc says nothing, but reaches out to perform the same maneuver. Sans clips through space and ends up behind him before he can complete the act.

“That’s kind of poor sportsmanship,” says Sans amiably, “don’t you think?”

The doc huffs as he whirls and attempts to turn him blue again. But he never had that same talent for blue magic. He never saw the point in studying the laws of physics at any great length. After all, he’d already learned everything there was to learn about them, hadn’t he?

There’s an astonishingly applicable moral about the pitfalls of pride, buried somewhere amidst all this. Or maybe shining brightly through the creeping murk of nonexistence, ready to nail Sans in the skull with the subtlety of a ballistic projectile. Like a metal spike. Or, possibly, a filed bone of some kind.

“I mean, you can protest until you’re blue in the face,” Sans adds, winking, clearing a boomeranging radius with a leap that takes a bit more effort than he’s accustomed to putting into his physical movements.

Stop talking, says the doc.

“Really, Doc, no need to look so blue,” says Sans.

Stop TALKING, says the doc.

“I know you apologize once in a blue moon,” says Sans.

Hold still, says the doc.

“But really, even you gotta admit that this kinda came outta the blue, don’tcha think?” says Sans.

You are trying my patience, says the doc.

“Like a bolt outta the blue, if you catch my drift,” says Sans.

The lights in his eyes go dark, and he stares at the doc with cold, grinning impassivity.

The doc hesitates.

Sans turns his SOUL blue.

With a harsh, screeching wrench of bones grating in sockets and phalanges trembling and floating hands dissipating in a spurt of magic in the doc’s unmitigated dismay, Sans sends him winging through the air, crashing into one of those fading-flickering walls, and brings a fence of ulnas slamming through him.

The doc utters a brief cry, louder than anything Sans has ever heard from him. Might be it’s outta surprise that Sans had something like that in him. Might be it’s outta shock that he’s suddenly experiencing a new kind of pain. The sound grates at his ears, or would if he had ears, and his skull is slick with sweat, his grin frozen and pained, as the doc tries to struggle free, only to find his movements slowed by the leaching, icy cling of having his SOUL being subjected so fiercely to the inexorable tug and pull of gravity. It’s like frost creeping up your bones, it’s like your whole body’s being dragged downward, like it saw the way things were headed, the crawl of magma to the core of the earth, and just decided to abandon all pretenses and commit to that downward press prematurely. It’s the hiss of cold through the marrow and the chill of something awful and ghostly.

So, that’s one physical constant that’s still here. Didn’t mess that one up too badly, Sans notes, ruefully. Check.

The bones don’t fade. The energy Sans can exert at any given time is pathetic, and especially feeble now, at the edges of his exhaustion, physical and mental. But he holds them there, his teeth set on a painful edge, lets the pitiable damage output cut through the doc again and again and stack up, tearing away at his hope and his pain and his drive, and the doc glares at him through the agony and hates him, and Sans can only dryly note that the doc should just join the damn club. He holds it, the long checkerboard of bones hard and taut and fierce with integrity.

He holds it.

He holds it.

He holds it.

He can hold it, but only for so long. He was never as strong as the doc.

An empty flask slips from its shelf and smashes on the ground.

“I’m real sorry about this, Doc,” says Sans.

If you were sorry, the doc hisses, warding away the second yank of gravitational force with a careless backhand, you would have stopped this long ago.

“Yeah,” says Sans. He doesn’t contradict him.

An empty flask slips from its shelf and smashes on the ground.

“You’re not doing this for the good of monsters anymore,” says Sans, with all the air of a joke, as the doc’s ferocious swipes and sweeps and blasting heat all miss in succession, “are you?”

He looks to the doc cheerfully. The doc doesn’t falter, and hurls two more looming skulls into reality. They nearly incinerate Sans on the spot, but he ends up beneath the table and they miss.

I am doing this because I must, spits the doc.

“No,” says Sans slowly, thoughtfully. “No, I don’t think that’s it. I think you’re doing this because you can.”

I am doing this because -

“You’re doing it because you can,” says Sans, his tone hardening almost imperceptibly, “and because you can, you have to. This isn’t about saving anyone or anything but your own pride.”

That is patently FALSE. The doc sends the table flying with a well-placed shinbone that shatters on impact with the hard metal but still knocks it into the wall with an angry metallic crash.

“Yeah, tell me I’m wrong,” says Sans, with a strange, vicious triumph. “You just can’t bear to admit failure, can you? Even if it signals, oh, say, the destruction of the entire known universe.”

The doc throws up a pair of blasters, whose yawning jaws scorch either side of where Sans was once standing, unflinching but no longer deploying that angry, unfocused concatenation of verbal castigations. The streaking heat tears out chunks from the walls - the walls, the walls, the walls that were never here. They may as well be drifting through some kind of bleak void unmoored, but the walls stutter like a tape recorder caught in rewind, the digital scratch of a claw over how it has never been, and they’re back and the lab is here again.

The room has assumed an odd, filmy patina, parts of it bleeding away. There’s a lack of chairs in this part of the lab, always has been. But was there always a lack of chairs in this part of the lab two or three or ten recurrences ago? Or did something swallow them up? Who’s to say his conceptualization of what a chair is has even remained untouched?

Nothing’s to say. There’s no baseline here, no way a surviving snapshot of the way things were, concretely, could’ve -

The lights in his eyesockets settle on the machine in the corner of the room. It may as well be leaping out at him. It’s the only thing that’s remained untouched.

He sighs, a low woosh of self-directed exasperation.

Of course.

The doc makes that lunging movement again, hands cutting the air in front of him, if it’s even still classifiable as air anymore, and a trio of scapulas carve toward him. They miss, one, two, three, and Sans throws up a hasty barricade of ribs, his fists balling at his sides, the stale scent of his own sweat thick in his nasal cavity, slick on the bones of his palms.

Now all that’s left is the question of getting things to align in just the right way.

Like stars.

Like planets.

“I took your hand,” says Sans. “I took it and held it and you took us to another world, or something near enough to it. You saved me.”

Had him doing equations from dusk till dawn, but Sans never minded that. He loved the stuff, loved sinking his mind into problems and tangling with them until the answer would yield to him like some kind of grail. And he would bear it proudly, until the doc dismissed it, and then he’d have to resolve to try harder.

Until one day, he decided to stop trying altogether. What’s the point in trying if it’s never goddamn well good enough?

“You’ve kept me here,” he continues, light and conversational, as if emotional subluxation were as simple as asking what one wants for dinner (it’s spaghetti, oddly enough. He never craves spaghetti). “You’ve kept me safe my whole life, Doc. And I owe you for that.”

The doc hammers stubbornly at his half-baked defense with a deft poise and celerity, as is his wont. Sans watches it crumble before their eyesockets. Another execution from one of those skull-like weapons of his should do the trick.

“So I wish I could be sorry about this now,” says Sans.

The doc says nothing.

“I really wish I could,” says Sans.

The doc says nothing.

“But, uh, funny thing? I kinda miss it.”

The doc tears away his barricade, ripping it asunder as if it were tissue paper, and Sans stops funneling magic into it the moment the flare of heat and energy starts shredding into the marrow. The thing collapses on itself, cannibalizing itself, and Sans is abruptly not there behind it anymore.

“I miss Alphys,” says Sans, both supraorbital ridges knitting down in grim realization. “I miss my life.”

Or lack thereof, really.

Destroying the catalyst won’t stop this. The only thing that will is to remove it from the equation entirely.

No cause, no effect.

The math is quite simple. Succinct.

He flits from one spot to the next with rapidfire pops of dissipating matter, and it’s a little bit scary how simple it’s become. There’s more negative space in this lab than there is real, actual matter at this point. The molecules are fraying at the seams, splitting, eviscerated by the plunging roar of nonexistence, more and more by the second. If seconds still exist at this point, that is. Measuring anything by increments has grown readily difficult. The gaps in space widen like bread dipped in water, stretching apart through no fault of their own. Nothing plies them apart, it’s just the way things are, the way they drift, the way the antispace is flooding in, unbroken and unfiltered. There was a clock on the wall, but there was never a clock on the wall. The clock on the wall never existed, as of something like thirty minutes ago. Relative to...something. He’s lost count. It’s funny how that happens, and he almost feels like laughing.

The doc can’t get a beat on him. He’s firing wildly, riding off uncertain principles and sheer guesswork. And the doc loathes guesswork.

“You ever hear the one about the man who fell through time?” says Sans, from somewhere behind the doc, just half a step away from the man himself. He’s so tired. Even the joke sounds tired.

The doc whirls on him, and Sans is no longer there. He blips to the space the doc was occupying some...immeasurable amount of time ago, his eyesockets cold and desolate and empty.

“Well, he told me to a-void the subject.”

He slams his hands into the small of the doc’s back, propelling him roughly forward. The doc stumbles, the trajectory of his path carrying him into contact with the machine that sits seemingly dormant in the center of the metaspatiotemporal chaos of the doc’s own making, and it roars to life with the earsplitting, high-pitched shriek of engaging circuits.

It exists beyond time, beyond space, and beyond everything. So what happens when it comes into contact with physical matter?

This isn’t how Sans would’ve chosen to find out.

The doc crashes into it -

The doc -

The doc -

The doc screams.

It shrills across the room, soundwaves broken and rippling and scattering in every possible direction, and in a few impossible ones too. A bright spark hisses in the center of the thing before it blazes, and Sans only gets one of his eyesockets covered in time before it bursts like a star gone supernova, matter and antimatter alike jettisoned from the epicenter of the calamity, chunks of rubble and tables and non-chairs hovering suspended before winding back again, and flying out again, caught in their own perpetual temporal loop, untethered, and the doc screams and clutches his face like he’s in terrible, terrible pain, and soon Sans sees why. Bright light sears out of his hands - no, through his hands, and their axes are fucked, they’re just well and truly beyond salvaging at this point, not even the flare of blue reaching into anything is enough to drag anything along a y-axis that’s ceased to exist, their tuples completely flipped on their heads like the deontological nightmares they are. There’s no charting it or accounting for it, and Sans is maybe drifting or floating, he’s certainly not standing relative to anything because there is no anything to be relative to, and T2 does not fucking = 1, or even -1, because if it did either of those things it’d be predictable and therefore a solvable problem. And the doc is screaming. It’s his eyes, his eyes, both of them, even the dead one, there’s something about them, something he saw or touched or felt, and there’s an awful light streaking out of them and it looks painful as all hell, because the doc hasn’t stopped screaming, his hands clapped over them but it does nothing, nothing at all because there’s twin holes punched through his palms and still the light and heat spills out and out and out and it hits Sans in his exposed eyesocket and suddenly he understands why the doc is screaming because he’s screaming too, it’s like getting a white-hot spike drilled through his skull, and the left side of his vision stains amber, and bright electric blue, and leaks in through his head and he can’t hold it, it’s streaming out too in pulsing, torquing, illogical waves and he wants to cover it, clap a hand over it, block it out, blot it out, tear it out of him because it’s like a bright, red-hot coal got wedged inside and it’s turning his vision to blotches of color and he can’t take it he has to rip it out but, but if he does - if he does he’ll get a hole in the bones of his palms just like the doc, just like him, just like - just - ͖̈̀̅͗ ̳̫̝ͨ͗̊ ͈̟̦̿ͪͤ ͧͪ͂̆̃͠ ̥̗ ̪͍̜̦̣ͫͤ̽̉ͬ̏ͤ ̡̝̖̜̙̖ͣ̄ͨ̇̆̂̓ͅͅ ̢̺̦͙͎̻̱̰̆ ͕̝ͫ̄ͤ̐ͨ͘ ̠͇͚̼͉͉͊͐̅ͧ ̈́̾ ͖̦̯́̀ͧ͌̂́́ ̤̱̜̍͊ͩͬ ̫̮̝̋ͬ͗̚͝ ̘̗͉͎ͣ̃͘ ̰̮͇͉̄̚ͅ ̘̮̰̘̬ͮ̐̈̂̆͒ ͈̩͖̭̆ͪͦ̐͘ ͭ ̍̏̌̍͋̔҉̠ ̼̞̪̩̝̲̜̓̾͑̈͐ ̯̩ͫ͛̒̚̕ ̡̲͂̋ͣ̒ ̸̟̀̽ͮͬ ̝̪͈̺̐̅ͨ͊̚ ͎̙̤̮ͩ͗̅̇̓ͩ̚ ̅ͭͤ͗̀ͨ ̞̠̫̗̱̬̓̎̃͞ ̉ͥͮ ̛̰͍̏̿ ̙̖͎͇̘̉ͦ́̉́ͅ ̟̩̩ͣ͒ͮͪ̉ ̭̰̟̬͔̫̄ͮ̍ͬ̕ ̧̳̇ ̨͚̝̺̫̄̓͌́̅ ̬͎̺ͣ̿ͦ͜ ̟̬͚͉̣̻̦̂̓͂ͥ ͊͌ͮ̈́ͤ͒̑ ̴̤ͬͪ͌ ͎̺̏̋̽ ̰͎͕̖ͬ͒͗ ̯̫͍̽͗ ̩̣ ̺̬̰̲̹̪̣̑͂̒̀ ̶̺̟͈͇̥̈͒̌ ̩̔ ͫͩ͑̌ͧ̅̈ͅ ̜͓̙̑ͫ͂̊̔ ̘̒͌͗̀ͭͨ ̡̠̺̥̫͓͙̥ ͕̗͊ͤ̊̃̈́ͩ̚͞ͅ ͍̘̳̫͈̺ͨ̔͌͞ͅ ̌ͬ͜ ͓̦̰̺̣̗̃͋̾͝ ͚̪͉̭ͬͯͅͅͅ ̠̪͎̗̾̽ͨ͝ ̢͎̣͕̩̀̋͑͂̏͛̌ ̲ͣͭ̅̈ ̺̞̺̗̜ͬ͒̔̀ ̹͉̬͖̩̤̼͒̕ ̱̬͈̆͂͒́͒͒͗͘ ͚̲͍̝̤̳ͥ̔̒ͧͤ͂͘ ͙̗̟͕͓̹͍̔̇ͪͩͤͩ̚ ̤̫͒ͩ́͆ͅ ̤̤̤̩̞ͥ̍ͩͨ̐͡ ̊҉ ͙̺̰̓͐̃̃́̚ ̳͓̞̤̩̠̒̀ͬ̈́ͯͤ̾ ̗̜͍̀͌̋͋͐ͮ ̸̼̪͇͇̦ͅ ͛̄͑̉̚ ̷̩̫̅̅͊ ̨͖̻̠̩̻͖̹͊̾ ̶̱͉̦͒̓ͦ̋ͪ͗ͅ ̠̘̱̰͖͍̣ͨ ̅͛͛̉̃ ̴̜͕͐̃̀̃ͩ ̼̭̤̤̆͌͘ ͥ̐ͫ͑ͣ̓ͯ͘ ̧̻̇̿ͤͪ͗ͭ ̧̼̱ͫ̋ͫ ̝͇̟͇̳̦̰͡ ̔́̄̈̀ ̢͕̱̦̪̖̞̠͐̆̿̏̊̒ ͈͇͓̺͓̫͇̇ ̵̲̮͇̫ͯ̉ͭͭ͊ ̼͔͖̉ͭ ̹̬͓̦̫͊ ̰̻͇̝̝ ̣̠̆ͬ̄̆͐͗ ̔ͨ̏ ͎͡ ̝̪̓̄ͫ͋͝ ͇̒ͣ̓ͦ ͚̅̉̓͑ͧ ̵̞̝͓̮ͣͮ͛̐ ̰͍̬̘̠̇̋̐ͦͣ̎ ̶̬̤̜̠͉͆͋̽͑̚ ̖̩̥̲̲̃̐̚ ͎͔͕͉͈̬̤͐̍ ̖̹̼̝ͯ ͎̀͂͑͐ͩ͑͛ ̫͙̗̺͙͖̞͋͊͠ ̹̗̀̓̑ͩ̀ ̲͓̥͔̣͇̟̔̃ͯ̃̚ ̘̱̱̼̻̫̥ͥ ̤̯̫͉̘͍̍͢ͅ ̡̩̥͇͉̬͔͕͆ ͖̰̝̲ ͙̠̔͐ͥ ̬̪ͬ ̹̟̹̬͚͓̻̌͊ͣͤ̀̃ ̰̺̘͔̮́ͯ ̷̣̖̼ ͈̣̤̭ͩ͒̀̌͢ ̒͗̓̉̂̅̈͏̺̣͕̪̤ ̵̩̥̻̩͙ ͕͆ͥͬ̈̎̇ ̶̹̙ͫ͐ ̞̻̣͕̖̠̬̃͒͐̇̔͑́ ͕̪͙̫̈́̑̽ ̼̗̗̱̘̹̍̈́͜ ̖̬̹ ͙̟̭͙͆ͦͫ̄̓̏ ̳̲̂͌ ͇̪̦͒͊ͨ͗ͪ̿͞ ̧̾ͯ͂ͨͤͬ̊ ̸̖̗̠̥̪͓͗̅͌ ͈̺̭̻̲̥͈̊ͨ ̮͈͕̟͍͇͕̏̔͒̊̂̏ ̯͔̜̤̲̦̻́ͨ͋͗͗ ̢̼̇ ̭̟ͪ̐̈ͤ̕ ̨̲͓ͮͤ͛ ̓̓̃ͮ͡ ̲͇͚̇͆͋ͬ̈͡ͅ ̶̉ͦ͊̐͂͋͋ ̀ ͉̟̎͌̈ ̴̹̫͓́ͧ͒͒̇ͧ̂ ̥̫̰̩̻̲̖̿ ͎̩̠͈̳ͮ̕ ̟̖̤͂ͯ͢ ̖̯̽ ͚͖̻̮͂ ̙͋͆ͮ̍͒͒ ̱̱̲̪̰̋͛̾̕ ͎̬͎̗̞͐̀ ̂ͮ̈͏̤̻͎ͅ ̧̣͔̥̙̘̠͒͋͐̚ ̵̖̘̟̫̪͔̹̊ͨ̀̂̂̓̔ ͅ ͛ͣ̄͢ ͏̳̼̰̗ ̟̤̣̪̬̀͜ ̩̟͐̇̏ͬ͗͌̚ ̦̭̭ ̰̤̻̙̰͚̹̍̔ͨ̾͜ ̴̟͐͊̈́̊ ͕̗͚͔̳̺̠ ̓̒ͬ̏̂ͬ҉̳̘̹͍̫ ̇́͠ ̵̖̟̼̭̟ͦ͆̔̄͌ͮͅ ͐͑ͭͧ͋͂͏̩͔̳̠̞ ͤ͑̋̍ͨ ̭̬̳͈̠̩̼̏͂ͨ͂ͩͨ̃ ͍͎͇̘̺̟̭̑ͬ ͚̦̳͙̮̐̇̃ͧ͗̃ͩͅ ̸̜̥ͬͭ͗ͪ ̰̹̩̯̝̻̤̏͆̓ ͮͮ̽̽ͯ̎҉͔̗̼̠ ̖̗̂̀ ̸̣̱͓͙ ͨ̏ͫ̍͡ ̻̻̫̙̣̈̾̊̂̊ ̪̬̲̺̪̞̇͞ ̖͙͉̙̞͛̃ͨͅ ̦̮̩̳̦̄̓̇̏ͥͬ̐͘ ̿ ̀̓̎̀͆͊́ ̢͓̝̬͖̫ ̝̼̦͉͓͋ͬ̇ͫ͜ ͑ͥ͏̞ ̡̳̜̤̟͙̆ ̴͓͚̍̓͊ͮ̈ ͯ̍͏ ͡ ̯̙͗͂̎ͪͣ̿͆̕ ̠̞ͧͫ̓͛ ̹̥̩ͭͩ̍ͮ ̱͋͌ͫͫ̚ ̟̠̫̺̂ ͙̫͓̻̟ ̮̝̗̰̘͉̪ͨ͑́ͦ̿͐̽͘ ̭̝̮̭̞̩̥ͤ̋ͣ̐̈́͗ͭ͜ ̟ͣ̌̈͌ ͎̗̭̻̆̔͐͌͒̌ ͕̼̈̌́ͮ̂̿̇ ̩̠ͫ̕ ̱͎̦̣͖̱̎ͯ ̸̠͖̳̜͍͈̋ͨ̋͐ͯ̈́ͦ ̺̞̗̘͒ͫ͛ͪ͑̀͜ ̛͆̿̐ ̡͉̗̱̰̜̍̈́͂ͪ̿̂ ̧̙͚̯͙̫̈́ͯ̃ ̸ͪ͑͆ͩ̓ͫ͋ ̨̱̭̭̦ͨ͗͂͐̑ͅ ̹͔͍͇͉̣̣̋̏ͦ͆͛̇̿ ̵̥̻̗̠̹͉͂͛͌ͭͫ̓ͤ ̖̤̖̃͌̂͋ͨ̽̀ͅ ̟͙̊̅ ̡̝͕̉ͅ ̠͇͎̝͍̥̲ͬͬ͗̒ͨ̔ ̢̏͒̑ͫ̋̃̚ ̵̺̪̻̗͔̀ͪ͌̽ͩͨ̊ͅ ̷͔͈̖ ̡̱̖̭̦̻̮͈ͫ̎͒͛̑̔ ̟͉͈̻ͯͨ̈̓̏ ͉̺̳̳̣̆́ ̡̥ͤ̅͒ͥ̂ ̦͕̰͙̼͍̙͝ ͔͍͕̟̭ ̭̗͔̀ ̡̔̚ ̛̰̩̯͉̳̼̙̋ͨ̎ͨͯ̉ͧ ͔͖̥͖̞̇ ̸̦̹̗͈͍̻͗͐ ̤̙͎͍͈̣̤ͥ̆̾̆ͭ̄̃͢ ̹̪͢ ͔͇̣͕͔̥̉̄͘ ̲͉̖͙̜̲̥̑̋͒̽̔̂̇͢ ̝̗̝̱̲͇̀͛̓̏ ͓̻̲̗͕̲̱͌ͬͬ̄̈́̒̈ ̗͇̬̲͇͓̗̃̿͆̆ ̥̹̙̭̪͝ ̨̱̦̺̲͚̤̳̀͊͑̆̇̽̾ ̩̗̟̙̇̒͝ ͯ̎̽ͩ҉͓ ̭͍ͫ̽̐̍͊̀ ͇ ͚̭̩̹͗̑ͅ ̿ͥͩ́̊҉̤̫͔ ͗̊̽ ̭͚̻̠͓͉ ͓̤̖͎͙ͥͅ ̷̭͚͕̰̼ͬͦ͛ ͐ͧͫ̒̈̂͏͎ ͩ̽̒҉͚̳̭̥̱̲͈ ̞͉̫̾ͤͭ̽̋͜ ̧ ͗ ̹̠͈̪͔̹͎̄͛͐ͥ̀ ͙̠͙͉̀ ̖̯̜̉ͨͮ̒ͨ͠ ̮̫͇͊̊ͣ ͙̪͍͔͎͚̫ͨͭͦ̿ͧͯͮ ̺͔ͭ̀ͥ̆ͥ̀͋ ͓̭̞͓ͥ͒̅͛ ͎͎͍̺̔̏ ͖̣̝͙͙͈ͭ̂ͬͫͣͭ̚ ̸̖͙̞̲͔͉͔̔ ̄͂̀͝ ̶̭̘̘̘̠̖͇̽͊͑ ̮͈̹͉͈ͥ̇͋̂͋̚̚ͅ ̭̰̰͉͕͖̠͠ ̟̲͈͉͛͐ͮ́ͨ͊́ ̜̮͚ͭ͟ ̖̖͈͕͉̟̟́̏ͬ̓̔̄ ̮͓͛̿̉͗ͅ ̤̣̣̖͕͎̈́̃́́ͯ̏̚ ͙̙̗̟̄̏̈́ͬ̐͝ͅ ̞̘͖͖̀ͤͥͪ ̢̦͖ͮͮ̅̀ͨ̋ ̙̀ ̭ͥ ̡͕̥̱̝̱̙ͪ ̦̼͎̏ͭ͆ ̨͎̞͓ͯ͒̏ͅ ͕͙̰̻̥͇̮ͩ ̤͛̋͑ͯ̑̒͌ͅ ͙͓̭̅̿͘ ̢ͣͦ̔ͣ ̴̝̹͕̰̖̬ͩ̄ͮ̓̈́͊ ̨̮̗͐̐̌̅̆̽ ̪̊̊ͥ̓̀ ̵̤͇͙̀̎̊̏͗̑ ͉̝̬͈̽́ ͕͖̱̮̱ͦ͜ ̦̅̈̈̃͑ ͚͔͢ ͔̱̣̤̥͙̺́ͧ̃ ̭̠̯̻͔̳̤ ̞̖̼̠̹̄̅̆̐̊͑ͅ ̬͚̆̽ͣ͛ͭ ̻͍͉̣͉̖̔͠ ̹ͩ̎̽́ ̶ ̭̪̙͊ͨ͒̒̒ ̵̞̦̆ ̭̩̝̝̣ͥ͋̓̄ ̮̭̰͔ͧ̅̉̉̈́ͅ ͙͕̼̤̯͎͊́̐ͅ ̤͓̬͆̌̋ͅ ̶̤̜ͅ ̞͂̈̉ ̹̮ͭ̿͋̅ͅ ̞̍͒͐ͩ̿̈́ͯ ́̆҉̣̙͍ ́͑̾̚҉ ͇͚͚̌̋̎͐̀ ̸̗̓̿̈́ ̳͚̫̗͎̀ ̲̬̺̮̹̎̽̑́ͮͩ ̖̫͍ͭͪ̽̋ ̶̣͔̤̥͓̋ ͍̤̇͂ͪ̇ ͈͙͖͒ ̫̲͕̫͊ ̊̔͆̊̈̅̂͏̦̯͖̯̹̣̺ ͒҉̙̬̞̳͓ͅ ̍͊̈͑͏̝̣ ̮͓̬͕̟͓͡ͅ ̨̻ͣ̌ ̘̪̰̬͉̠͟ ̢͈̠̦̦̯̿ͪ̀̐̚ ͒̐̚͞ ͑ͤ͆̾͏̬̦̯͇̳̪ ̩̩͎̠̏͆̃̆ͫ́ ͕̳͗ ͋ͩͨͯ͏̦̲̖̳̥͈̠ ͎̬͔̫͙͙̇ͦ̃̚