He's always had a shit memory.
He's pretty sure he has, anyways. Like, maybe seventy-five percent on that. He obviously has no way of knowing if he's actually right because, y'know, it's not like he'd remember.
It kind of comes and goes in waves, far as he can tell. Sometimes—good days, although the qualifier is probably far too optimistic for what those days are actually like—he’ll just kind of keep forgetting where he put things down.
He leaves a glass half-full on the kitchen table and pours himself another before he realizes. Forgets his jacket in his bedroom closet and spends twenty minutes frantically searching the living room for it. Loses his keys. Locks the front door behind him without said keys a couple times, actually, and has to just huddle pitifully on the doorstep until Papyrus gets home at the end of his shift. He drops his gaze down when it’s time for the small gaggle of children to make their daily trek home from school. He can’t make out what they’re whispering, but the way they keep glancing at him makes it pretty apparent who their subject of ridicule is.
He even manages to lose his phone once, fallen from his pocket and vanished somewhere in the apparent void of snowdrift between the corner shop and their house. By the time he finds it again—four hours on his hands and knees in the snow, he can’t even feel his hands—there are eight missed calls from his brother.
Pap backhands him for that one, hard. He can't lie properly on his left side for a few days after without the edges of the new crack in his skull grating together, impossibly loud in his head, agonizing claws on a chalkboard.
That particular lesson never needs repeating.
The bad days, though—man, the bad days, he forgets what he's doing right smack in the middle of doing it. He'll be cracking eggs into a skillet for breakfast and suddenly it's like he's stuck, glitching, staring at his own greyed fingers curled around the brittle shell like they belong to someone else, because he can't remember if he was making an omelet or fried eggs or the hash scramble Pap likes so much, and showing up with the wrong breakfast is tantamount to not showing up at all.
Even worse, he knows Pap told him, he knows it, he remembers nodding along like a fuckin' bobblehead doll at the instructions, but it's lost somewhere in the churning waters of his own traitorous brain.
And then he just kind of hyperventilates until the eggs burn anyways, so. It's not like it really matters.
He does remember, though, with blistering fuckin' clarity, the very first time he saw Papyrus successfully take down the Captain during practice. It's one of the few things he's got on technicolor repeat on the inside of his skull, the moment he watched his little brother smash the closest thing he had to a friend into the ground, all his sharp teeth bared in a rictus grin, and realized that the toddling little babybones that he'd raised was well and truly gone. Irrevocably gone. Never-coming-back kinda gone, and sans studied the cracks creeping like vines across Papyrus' left sphenoid bone, a slick, hot feeling in the back of his throat he didn't recognize.
He’d always known he’d be an absolute shit parent.
Papyrus was a feral thing in motion, capable of hauling his sizeable frame at a pace even the limber Captain had some trouble competing with. He towered over her by at least a head, and his bones—healthier than sans, thank god, there'd been a few years there Pap didn't seem to be growing so fast, but he'd shot up at twelve and not stopped 'til he hit twenty—are powerful, dense things, heavy and toughened in stark, humiliating comparison to his own birdlike fragility.
When Pap hit, he hit hard as a goddamn freight train. Undyne was good, really good, twisting out of his way, constantly ducking out of his eyeline, but even she could only avoid him for so long before she slipped in a fresh patch of ice and Pap seized his opportunity.
With a dull thud and a cruel blow to the gills, he sent her flying into the rough black bark of a nearby tree. Sans winced at the sound she made, this horrible, brittle snap! that hopefully had more to do with the frozen tree than her actual bones. She slid, wheezing and pale, to the tangled roots where she crouched in the dirty snow, gasping for air.
"You prick," she huffed happily, gave herself half a second to recover having the literal wind punched out of her, and then somehow she was up, she was on her feet. She was grinning like a lunatic, like it was her birthday and Gryftmas come all at the same time. Before sans even really processed that she’d lunged at Papyrus, she landed a vicious kick into the plate of Papyrus' right knee. Sans inwardly cringed as the bone slid, accompanied by a dull crunch way, way too far to the side.
Papyrus dropped with a grunt and Undyne fell back, circling him like a tiger while she waited out his next move. It was clear she intended to wear him out—Pap was a bruiser, but sans knew from experience it took a lot of energy to throw himself around like that, and he’d overdone it trying to land the first blow. He winded fast. Undyne loved nothing like the long game, and she had the stamina of a goddamn wolf.
The thing was—and this, he remembers often as he stares blankly at the cheap plastic glow stars stuck to his ceiling, feverishly twisting his fingerbones into his bedsheets like the repetitive motions might somehow exhaust him enough to finally sleep—the Captain, despite the way she was breathing kind of funny now, was smiling. She looked like she was actually having fun, like it was the best day of her life, getting the shit kicked out of her by her second in command. She was a shark with the copper scent of blood in the water, all her jagged teeth on proud, bristling display.
They'd done this when they were kids, too, Paps and Undyne. Every time there was a display like this, a final violent overflowing of the rivalry boiling between the two—which happened roughly every six months—sans had to stare at his own sneakers for a long time and remind himself not to think about anything like—
—like that one time that he'd had to patch up a skinned elbow when Undyne, reckless little whirlwind of a demon that she was, had somehow managed to get herself shoved off the porch roof and onto the hard-packed dirt of the front walkway.
Papyrus had watched, arms folded stubbornly over his chest, as sans took her tiny scaled hand and led her inside. He had not apologized.
"You're pretty good at this," she'd observed, kicking the heels of her tiny combat boots at the side of the bathtub. “From listening to Pap, I didn’t think you were good at anything.”
Sans thought he'd had a crippling headache that day—heh, but to be fair, when did he not?—but he'd said nothing in response, only set the first aid kit out on the floor next to him with a practiced kind of ease. He wondered how they’d managed to get up on the roof in the first place.
“Shut your eyes. This might hurt," he'd offered, and that was all the warning she got before he proceeded to upend a plastic bottle of vodka over her bleeding arm.
Undyne had promptly shrieked at the pain and bit him, more out of reflex than anything, her tiny needle teeth clamping down hard on his exposed forearm.
Much to her surprise, they'd sunk straight into the bone, right down to the root, like sans was made of rice paper. Undyne sputtered in shock and let go--she'd bit Papyrus before, many, many times, and it was exactly as pleasant as choking on a bone accidentally left in her food.
Sans hadn't reacted. He'd made no move to pry her off, or any indication that he'd even felt her teeth. She'd pulled back like she’d been burned, the taste of dust crumbling awful and cloying like powdered sugar on her tongue, in the back of her throat. Gross. "Uh, sorry," she’d muttered before she quite remembered to stop herself. Even worse, she then followed it with "Hey, uh, are—are you okay?”
The tiny pinpricks of light in sans' eyes had flickered, guttered out and died, leaving her locking gazes with empty black sockets. “what do you mean, kid.”
She shrugged, suddenly uncomfortable. “does…does Pap get hurt a lot or something?” She made a vague kind of motion towards the medical kit. He’d stared at her like that, blank, silent and still for a long time. Long enough for Undyne to start to squirm under the scrutiny. She didn’t really enjoy staring down a grim reminder of her own mortality, thanks.
Then he'd chuckled, this low, hollow laugh she'd never heard him make before.
"hey," he'd said instead of answering her question, his chipped fingers deftly unwrapping a bright purple (!!!) bandage to cover her wound. "you wanna hear a joke instead, Little Miss Fish? Why did Sally fall off the swing?”
She had squinted at him, suspicious. He was dodging. She hated when adults did that. “Dunno. Why?”
“Because…she had no arms.”
She’d paused for a moment, blinked her big yellow eyes at him and then cracked up laughing, this enormous bark of a thing that made sans’ eye sockets crinkle at the corners in amusement. “You like that? Man, okay, you’re gonna love this one. Knock, knock.”
‘Who’s there?” she had demanded eagerly.
“Definitely not Sally!”
Undyne had been so pleased, she’d barely punched him in the arm hard enough to bruise.
Undyne was playing with Papyrus, now, taunting him, darting under his swings to tag him and daring him to try tagging her back. For all the world, the fight looked very nearly friendly, but sans knew few things quite so well as he knew his brother. He knew, intimately, the whipcord lines of tension in the lines of Papyrus’ shoulders, the way he gnashed his teeth together until sans’ own mangled mouth ached in sympathy, and he knew Papyrus wasn’t there to have a good time.
He wondered if Undyne had any idea that their biannual sparring matches were only practice on her part. He wondered if she knew Papyrus would slit her throat, given half a chance.
He thought she probably did. Anyways, it was just her luck (?) Asgore had a regular habit of turning up to these events. He seemed to enjoy watching his subordinates beat the hell out of each other, and Papyrus was hungry, not suicidal.
Mechanical, stiff, joints aching with cold, sans somehow managed to uncap the flask in his hands and take a long drag. It did nothing to settle his uneasy stomach, the burn of it almost threatening a reappearance in the back of his throat, but he screwed his eyes shut and choked it down like he'd done a thousand times before, like he'd do a thousand times after. He swallowed, and fished a cigarette case from his pocket, flipping it open one-handed with a kind of practiced ease. He quickly plucked out three pills, downing them with another long drag of the gut-rot in his flask before he really had to look at them, and the case vanished into the puffy depths of his coat.
Sans had been sitting flat on his ass in the snow on the sidelines of the sparring rink for a solid twenty minutes, cold seeping in easily through the thick cotton of his sweatpants. He was pretty sure he could feel it in his marrow and he was shivering like he'd been locked in the shed for a week by this point, but still, stubborn beads of sweat pricked at his browbone. Still, he could feel his cheekbones flushing pink and damp, chipped hands trembling bad enough that he had to shove them in his pockets just to stop himself looking at 'em. The whiskey burned in his chest, but it didn't actually stop a damn thing.
Inside his pocket, safely away from Papyrus' watchful eye, he picked fervent at a nasty chip across his left pointer finger with one claw. He dug into it until he could hear a soft crackling like tree branches, until he could feel a bright, violent sting of something warm and familiar coiling in his belly.
It didn't help, but it sure as hell didn’t hurt.
He was fine. He was fine, he was fine, he was fine. He was, very much in spite of himself, actually having a pretty alright day, up until Papyrus had unceremoniously dumped him at the feet of the Captain’s mate—a short, sort of pleasantly round lizard with a heavily scarred snout, wicked teeth, a familiar-looking labcoat, and large amber eyes fixed resolutely to the screen of her phone. Papyrus had growled,“Hold onto this thing, will you,” at her and shoved one end of Sans’ leash in her hand. She’d promptly looped it around her wrist, leveled a warning glare his way, and proceeded to ignore him.
From the sound of tinny musical beeping, she must have been playing a game on her phone. She didn't seemed overly concerned at Undyne's takedown, although sans thought that even if she was, she was also probably far too smart to react here, in public, where anyone could see. She managed to claw her way up the Royal Scientist, after all, years before she even knew Undyne, and she must know how tentative her hold on the position is. She must how vital it is that she and her mate present a united front, a powerful front, a show of solidarity in the face of absolutely anything, so her claws were steady on the buttons. She didn't so much as glance up when the Captain made a strangled noise of what might have been pain on a lesser monster.
Sans wondered how she did it. He'd finally managed to stop himself flinching every time Pap took a hit, but that was a long, rough process. And anyways, the Scientist didn't look like the sort of monster to let her mate smack her around, Captain or not.
While he was busy staring at the Scientist—did he know her? he didn’t know her, he knew of her, everyone knew of her, but they’ve never met, she hasn’t even spoken to him, so why is there such a horrifying comfort in huddling at her feet?—there’s an awful noise from the ring and sans’ head whipped around just in time to catch Pap’s broad fingers curled around the hilt of his blade, pressed into the Captain's gills. The sparse crowd went abruptly silent, one collective breath held at the impossible sight of their commander on her back.
"Yield," Papyrus had hissed viciously at her. And he should have been marveling at this, probably, at the fact that his baby brother had just laid out his Captain, at the raw power sparking in his powerful bones and between his clenched teeth, but all sans could think as the Captain tipped her head back to accept the customary notch below her jaw that indicated she'd been defeated, was oh, hey, lookit, his hands don't shake!
The Captain snarled, and bared all of her awful teeth at Papyrus, cheeks flushed dark blue in humiliated rage. She spat at him. She kicked fitful little groves into the snow with her heels. She looked as furious as sans had ever seen her, but her remaining eye glared up at his brother, narrowed with calculating glee and that—well, that was new.
Sans tried to imagine her looking at him like that, and it sort of made him want to curl himself into a tiny ball and hide forever. He huddled further into the unruly ruff of his coat at the mere thought, shivering, but Papyrus's broad hands held steady as a surgeon's as he dragged a shallow line through the Captain's topmost gill.
She didn't flinch. There were only four lines above it, and sans knew at least two of them belonged to the king. No shame in that—Asgore was easily four times her size with the added bonus of being terrifying, and the fact that she’d even lasted a round with him as a loudmouth teenager was nothing short of a miracle, he was fond of reminding her. A third (if the rumor was true) belonged to Her Former Majesty, which is too horrible to think about. The fourth one, she kicked sans in the head for asking about. The fifth, now, belonged to Papyrus.
His brother was so goddamn cool.
She beat Papyrus' ass three times in a row for it, made the point abundantly fucking clear that she was still in solo command of this ragtag ship. She broke Pap’s collarbone in retribution right before she chipped a last ragged chunk of bone out to mark her victory.
The whole time through, he didn't make a sound.
She’d started marking Papyrus's notches off in bundles of five years ago, back when he was first accepted into the academy, and she's made it all the way down his neck now, across his clavicle and started in on his sternum.
They're the only injuries sans was expressly forbidden to touch. They’re also they only ones sans actually sorta wanted to.
“You must be very proud,” the Scientist said, still without looking at him. Her voice was clipped and cold. “To have a brother so formidable as to even offer a challenging workout for Captain Undyne.” She smiled, and it looked like maybe she’d only ever heard the expression described before in books. He wondered if she called Undyne ‘Captain’ when they were alone together. He hoped not.
She tugged thoughtfully at his chain and sans jerked forward, choking. “You, on the other hand, well. You’re a bit of a glass cannon, aren’t you?“
Sans blinked once, twice, and then—
he’s not at the ring anymore, he’s not anywhere, he’s in the basement of a place that doesn't exist and he’s naked and he’s trembling all over and you’re a bit of a glass cannon, my boy, off the charts, you are completely off the charts but you’ve got to be fast, fast, faster no faster than that you useless sack of bones, I said move it you’ll get yourself dusted the second they land a blow do you understand me are you even capable of understanding me you idiot—
and sans understood, of course he did, he’d understood his place from the day he’d blinked awake on the lab’s cruel steel table and immediately been kicked to the floor, but he hurt, he hurt so badly and he couldn't make himself move—
He’d never been more grateful for Papyrus’ crushing grip around his shoulder. “We’re done here,” his brother deadpanned in his general direction, sounding for all the world as though he isn’t bleeding profusely from the collarbone. sans breathed a tiny sigh of relief as he retrieved the leash from Alphys’ lax claws. She didn’t fight it.
“Until next time, sans!” she called after them, “I’d love to hear more about your work!”
They’ve barely turned a corner before Papyrus landed a clenched fist squarely on the back of sans’ skull hard enough to send him stumbling forward, his entire field of vision suddenly filled only with bright bursts of pain.
“What did I say about running your mouth in public, what did I say about interacting with other monsters, what did I say about how goddamn easy you are to kill,” Papyrus snarled at him and grabbed hold of the brass ring affixed to sans’ collar, abandoning the leash in favor of lifting him up onto his toes. Sans scrabbled uselessly at his throat and tried to remind himself that Papyrus probably wouldn’t murder him out in the open like this.
“Sorry,” he choked. “S-sorry, Pap, I’m so sorry—“ Another blow to the skull dropped him to his knees in the snow. Blinded, he barely managed to catch himself on his damaged hands.
“No,” his brother spat, and then there was a harsh weight on his spine—Papyrus’ boot, a massive, thick-soled affair, crushing him dispassionately to the ground like he’s an insect that holds some faint passing interest.
Sans made a strangled kind of wheezing sound as the boot pressed cruelly down on his ribcage, bones creaking in protest. He’d be willing to bet Pap’s got a smile on his busted face a mile wide, if only sans could twist around enough to see him. He wanted to see it.
Papyrus crouched down over his prone form like a predatory bird, his knee digging sharp into sans’ shoulder blade, and stroked a fond hand over the cratered ridge of sans’ cheekbone. When he finally spoke again, it sounded very nearly fond.
“No, sans. You’re not sorry yet.” Sans shuddered at the unsettling feeling of two of his brother’s fingers hooking themselves into his eye socket and dragging his head around to meet Papyrus’s coal-bright eyes.
“But you will be.”