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Unexpected Guests

Chapter Text

The TV flashed as the heroine let loose a blast of energy from her wand, and though Papyrus questioned the realism of the magic system he had to admit this battle was quite climactic. Anime wasn’t really his thing—certainly not as much as it was Undyne’s—but now that they had the good stuff from the surface instead of literal garbage to watch, there were a few series he could admit were pretty good. It had become a tradition now for Undyne to come over some afternoons toting a bag of DVDs or Alphys’ hard drive, and they’d sit on the couch and watch the latest thing she thought he’d like.

Today’s selection was another magical girl anime—those were Alphys’ favorite so it tended to be a common pick—but the battles packed a real punch as the protagonists learned to trust each other and use their strengths to fight invading creatures from another dimension and save both worlds from a corrupting evil. It was a little scary sometimes, but Papyrus liked how clever the characters were getting with their magic—as someone who prided himself on his magical prowess he could relate.

But today was extra special because not only was Undyne sitting beside him with fists clenched and a broad grin on her face as she rooted for her favorites, but Sans and Frisk were here too. Toriel had asked the brothers to babysit the child while she attended a conference for educators, and the skeletons had been more than happy to oblige; so far though, they hadn’t gotten into any shenanigans until Undyne had showed up with entertainment. Papyrus glanced down at his human friend and grinned; they were leaning forward, wearing a determined smile as the protagonists teamed up to combine their attacks and send an arcane circle weaving around a horrendous spirit, cleansing its soul. Sans sat on their other side and watched with lidded eyes—Papyrus was always surprised to see he could stay awake for these things. Maybe he actually liked them?

As the team united to unleash their ultimate technique against this season’s boss, Frisk seemed to remember something and nudged Papyrus’ arm. He glanced down at them, and waited as they signed.

Hey Papyrus… you never did show me your special attack. What was it?

“Oho! That’s right! That pesky dog got in the way any time I tried, but I haven’t seen hide nor tail of that little pest for some time now!”

“Shh, Papyrus!” Undyne barked, eyes still glued to the screen. “You’re gonna miss the best part!”

He gave Frisk an apologetic glance, but they nodded, and they both turned back to the action. The boss writhed under the summoned spirit of all the girls’ spells combined, and exploded with light as the wicked magic twisting it was extinguished. The surrounding lands were purified at last, and the protagonists celebrated with a group hug, beaten and worn as they were. When the credits rolled, Frisk applauded while Sans turned the lights back on, and Undyne stretched.

“So that’s it for that season, but the next one is coming out in a couple weeks,” she explained. “Me and Alphys are gonna have a little party for the season opening, you guys are TOTALLY invited.”

Sounds great,’ Frisk replied, smiling. ‘I really liked that none of the monsters were really evil.

“I KNEW you would! Um, so did we,” Undyne grinned. “Anyway, what were you talking to Papyrus about?”

Oh! When everyone went to use the special attack, it reminded me I never saw Papyrus’,” the child explained again. ‘I forgot all about it until just now.

“Huh, really? He’s super proud of that, I can’t believe you missed out,” Undyned uttered, grinning. “Well, I know I’M all pumped up for awesome magic, and there’s only one way to fix this! So! Let’s TOTALLY DO THIS!! C’MON!”

“Yes! Now is the perfect time! But the house is not the perfect place!” Papyrus added with some concern. “The special attack is very, er, laser-y, and I’m not cleaning that out of the carpet.”

“Outside then! C’mon punk, wait ‘til you see this! It’s AWESOME!” Undyne yelled, then grabbed Frisk by their head and charged out. Papyrus glanced over at his brother, who hadn’t appeared to move from his spot on the couch even after turning the lights back on. “Well, I suppose this is happening. Are you coming?”

“i’m getting up as we speak,” Sans answered, mischief gleaming in his eyes.

“You’re not moving at all! Ugh!” Papyrus turned and walked to the door, and Sans appeared at his side as he headed out.

“nah, you know i wouldn’t miss watching you be cool for the world. wonder how the kid’ll react. i bet it’ll be hilarious.”

The front yard of the brothers’ house wasn’t as large as the back, but it was still sizable and allowed for plenty of room. Undyne waited with Frisk on the driveway, an eager smile baring all her fangs as she watched the brothers approach. Frisk was rubbing their head, but smiled nevertheless—clearly they were excited about this too.

“Okay! Since Toriel would kill us if we hurt Frisk, I’M gonna be your opponent!” Undyne declared. “Just like old times, right Papyrus?”

“Indeed!” he agreed, grinning. “I’ve missed our training sessions! We mostly cooked… but I’m sure the same principles apply!”

“Yup! You gotta do everything with ONE HUNDRED PERCENT EFFORT or it DOESN’T MATTER! Fighting, cooking, saving the world—IT’S ALL THE SAME!” Undyne bellowed, clenching her fists. “If you don’t believe in yourself, what else have you got?”

“Precisely!” Papyrus agreed. “Though, even if you don’t believe in yourself, as long as you have friends who do, you can still do anything!”

“AN EXCELLENT POINT!” Undyne roared, stomping the ground. “Okay! Enough talk! SHOW ME WHAT YOU’RE MADE OF!”

Wouldn’t that be bones?’ Frisk signed, wearing a smirk.

Sans, who stood next to them, chuckled. “yup.”

The exhibition battle began with the two friends warming up; Undyne tossed some spears after Papyrus had cast a few bones her way, and they both used their soul magic on one another for a turn just to get into the swing of things. But neither Papyrus nor Undyne were ones to do things by halves, which meant even the friendliest of battles between them didn’t stay casual for long. Frisk watched in awe of their friends as each wove increasingly intricate patterns with their attacks, dodging and blocking each other’s work skillfully. Sans noticed their expression and laughed softly.

“my bro really is cool, huh?. undyne’s strong, but no one can control their magic half as good as he can. he’s really giving her a run for her money today.”

As he finished, Undyne let out a roar, and sent a volley of spears cascading down. Papyrus, with his soul flashing green, held fast and blocked them all with a conjured bone and a confident smile. His mentor’s soul spell dropped with the end of her turn, and he cast his weapon aside. He passed a wink to Frisk, and struck a pose.

“Now! It is time! Inspired by the spirit of cool anime and my inherent greatness, I! Give you! My special attack!!!”

Papyrus flicked his wrist, and something flashed into existence. A low, horse-like skull nearly as long as he was tall emerged from the ether, glowing eyes with rounded pupils flaring in its sockets—then a long, spiny vertebral column followed. Delicate, birdlike limbs alighted on the ground to support a lean torso and deeply keeled breastbone; expansive, narrow wings fluttered up from its shoulder blades, and the being lashed its whiplike tail with a flourish before crouching, gaping with a split maw and baring solid, chisel-shaped teeth. Magic thrummed from between the mandibles—

And was cut off as Papyrus wrapped his arms around the creature’s jaws and snapped them shut. The beast’s irises flashed into a mirror version of Papyrus’ own wide-eyed expression, and the two wrestled for a bit while everyone else could only stare. Despite the creature being many times his size, Papyrus wrangled it into submission, scolding it all the while like it was a misbehaving dog instead of the giant, skeletal dragon thing it was.

“No! Bad! Down!” he shouted, wagging a finger in the beast’s face, and it finally laid down with a strange sort of whine.

“What… the HECK?!” Undyne shouted, tossing her spear aside. “You’ve never done THAT before?!”

What’s going on? Is it not supposed to look like that?’ Frisk signed, only having everyone else’s reactions to go on.

“Ugh! No!!” Papyrus huffed, clearly frustrated. “It’s only supposed to be a cool skull, but then THIS happened!”

He gestured at the creature, which sank lower under his disapproval and crooned a sad-sounding rumble. Frisk almost felt sorry for it, but wanted to laugh too—there was something silly in such a large, scary-looking thing being afraid of Papyrus. But if it didn’t normally manifest this way, why had it done so now? They thought for a moment and grinned.

Papyrus… you really were inspired by anime! You summoned a spirit just like Minako did,’ they said, and Undyne howled with laughter.

“Oh my GOD! That TOTALLY EXPLAINS IT!” she hooted, and Papyrus ran a hand over his face with a weary sigh.

“I did say as much, didn’t I?” he admitted, then looked back at his creation. “I certainly didn’t think it would have any real effect, but here we are. Alright, you’ve done well enough. You may go.”

He waved his arm to dispel the construct, but it simply stared up at him innocently. He waved his hand again, frowning, then both hands in a shooing motion. “Off with you! Go! Shoo! I have no need for your services at this time, the fight is over!”

The creature made another sad warble.

“Aw, I think it wants to stay,” Undyne said lightly, walking closer to the creature. “Hey, what do you call it, anyway?”

“Well I never had occasion to call it anything other than my special attack,” Papyrus answered, planting his hands on his hips. “It’s usually not this stubborn.”

It also doesn’t usually have a body. Maybe you put too much effort into it,’ Frisk mused, and he brightened.

“Of course! I would do nothing less! I just thought I had always given my attacks my all, but apparently I had more of my all to give all along. Incredible! What heights will the Great Papyrus reach next?!”

“so, can we keep it bro?” Sans teased; he was looking a lot more relaxed than he had when the creature first appeared. “you always wanted a puppy.”

“I’ve had quite enough of dogs since then, thank you very much!” Papyrus retorted. “But until it dissipates on its own I suppose we have no choice. But it’s not allowed in the house!”

The creature gave a huff.

Can I pet it?’ Frisk asked, and Papyrus shrugged.

“I don’t see why not! Though it very clearly is a large and dangerous attack and not a dog.”

Frisk trotted over, and held out their hand warily like they always did with strange dogs. The creature extended its long neck and sniffed, dry breath huffing over Frisk’s head gently and ruffling their hair. Then it purred and presented the top of its crested skull, and Frisk ran their hands happily along the smooth bone. Undyne joined in, and before long they had one very contented special attack rolling on its sides begging for more.

“aw, it really likes you guys,” Sans said warmly as he plodded closer. “all thanks to my bro’s good influence, no doubt.”

“Naturally!” Papyrus affirmed. “I admit I had no idea it could be so… personable. Are yours like this, Sans?”

Sans froze as everyone’s eyes fell on him, and scoffed nervously. “heh, you know i don’t have anything as cool as your special attack. laser skulls are too much effort for me. laser dragons? totally out of the question.”

Papyrus stiffened. “Of course, brother. How could I possibly have thought otherwise?”

“No, hold on, don’t cover up for him,” Undyne growled, her eye darting between the two. “If Sans has this kinda thing too, I wanna see it.”

“You heard him, he’s far too lazy for such a cool attack!” Papyrus swiftly answered. “Though I’m sure if he practiced, he too could possibly approach my greatness!”

Frisk frowned. They’d never seen Sans fight, but it made sense for the brothers to share attacks—they were so close, and though opposites in many ways they had plenty of similarities too. Maybe if they asked nicely, they could convince him to show his stuff.

Please Sans, I really want to see your attack! I bet it’s super cool,’ they signed, wearing their sweetest smile.

“Not as cool as mine,” Papyrus grumbled under his breath. He was idly petting his new friend.

Sans studied Frisk closely, then shut his eyes. “that look on your face… you’re pretty serious about this, huh? well, i hate to disappoint, but i really don’t have any magic like that. my bro’s just that cool.”

Frisk scrunched up their face, and Undyne laughed in the background.

“hey now, don’t let it stick like that,” Sans teased. “here, i’ll throw you a bone.”

A tiny bone no longer than one of his fingers appeared in his hand, and he tossed it lightly. Frisk caught it, and gave him a look. As they examined it, it crumbled to nothingness, and they frowned at him again.

“see, i can’t hold a candle to my bro,” Sans said with a shrug. “no point in dragon this out any longer.”

An indignant groan rose from Papyrus and his beastly companion at the same time.

“Sans.” Undyne had her eye closed—she was doing her dramatic thing where she was definitely picturing herself in some kind of anime. “Did you really think you could hide something like this from us?”

“not hiding anything if there’s nothing to hide,” he answered, shrugging again, but Frisk poked him in the side repeatedly, and he chuckled as he tried to stave off their darting hands. “whoa there pal, if you wanted a rib-tickler you just had to ask.”

You’re such a liar!’ they signed, laughing softly. ‘You hide all kinds of things, you jerk!

“geez kid, harsh much,” Sans replied, shaking his head. “what if tori heard you saying that?”

What if she found out you were lying!’ Frisk shot back before continuing their poking assault.

“you’ve got no evidence of anything. i cannot believe you would slander your old pal sans like this, you should be ashamed.”

You’re the one who’s got codewords and secret rooms! And—

A spear suddenly buried its head at their feet and the two looked up at Undyne, who wore a snarl. “You kids… ARE JUST MESSING AROUND! Sans, what are you, FIVE?”


“He’s like, twenty-seven actually,” Papyrus corrected helpfully.

“Oh my god. That’s even worse.”

“Tell me about it.”

Undyne scoffed, pinching the bridge of her nose. “Fine. FINE! If Sans won’t show off his stuff on his own… I’ll MAKE HIM!”


Undyne cast her magic before Sans could make a move, and Frisk watched with interest as the battle began anew. The short skeleton glanced down nervously at the little spade-shaped flash of green that was his soul, and gave a resigned shrug.

“welp. go easy on me, ok? not everyone is as tough as my brother.”

“Please,” Undyne sneered, “you know I don’t go easy on ANYONE!”

She cast the first volley of spears, and Sans eyed them wearily before summoning a wall of bones to block them. Frisk noticed his feet shift anxiously—he clearly wanted to move, but the green magic kept him locked in place as more spears headed his way. Based on the sweat beading on his skull, this was not a comfortable position for him in the slightest. Having been on the receiving end of Undyne’s fury, Frisk couldn’t blame him.

“so… if i show you my special attack, you’ll end the fight?” he asked after blocking another round.

“Yeah! Frisk, me, heck, even Papyrus wanted to see you pull it out!” Undyne replied, beaming. “C’mon, just one turn! Is it so hard to do that for your friends?!”

“fine, fine… after this then. you better be ready.” He surprised her by actually attacking during his turn, though it was a pattern she was familiar with from training with Papyrus. When it was his turn again after another round of blocking spears, they all watched eagerly… as he did nothing.

“yup. that’s my special attack. told you it was nothing, didn’t i?”

Undyne screamed in frustration, and sent down a rain of spears out of turn. Above the air whistling through their blades, Papyrus was yelling, and all of it was drowned out in an instant by blinding light and thunderous shocks that shook the ground. In its wake, the yard was left in silence; Frisk blinked lights out of their eyes as they tried to stand, their legs shaking. Papyrus was clinging to his familiar, and they rattled together while Undyne hauled herself up with a spear.

In the center of it all stood Sans, his sockets dark. At each shoulder, he was flanked by sturdy, beastly skulls with needle-sharp teeth and a cruel slant to their unblinking eyes. They hovered, steam curling around their fangs before they drew back and faded out of sight. These attacks didn’t look like anything Frisk thought their jokey, round little skeleton friend was capable of.

“there. ya saw ‘em. happy?”

“That… was… holy crap,” Undyne breathed. She gave up on the spear and flopped back into the grass. “Geez Sans. What the actual…. You’ve been holding out on us. This WHOLE TIME. BOTH OF YOU SKELETONS, OH MY GOD!!!”

“calm down lady, you’ll blow a gill out,” Sans huffed. “my bro’s is definitely cooler. ‘m gonna go take a nap, that was enough excitement for me today.”

Frisk frowned as he walked by to settle under a nearby tree—wanting to be away from the action, but not too far either. They watched him get comfortable and doze off, then turned to see Undyne trying to noogie Papyrus but being foiled by his lanky draconic companion. It growled pleadingly at her, but a warning snap earned harsh scolding from its master and it finally retreated to whine from a distance as Undyne put her friend in a headlock.

“YOU NERDS! YOU HAVE ALL THIS SWEET MAGIC AND YOU DON’T EVEN KNOW WHAT TO DO WITH IT!” she hollered in some strange mix of joy and frustration. “I cannot BELIEVE—!”

“Ugh—Undyne! Please release the skeleton!”

“NO! Not until you TELL me why you guys HELD OUT ON ME FOR SO LONG!”

“It’s not that special! Grk—Undyne this is really not a position that is conducive to conversation!”

Undyne, let him go,’ Frisk signed, but it went overshadowed by an affectionate suplex. Papyrus’ familiar yelped in concern as they thudded on the lawn, and he was left massaging his spine as Undyne sprawled out next to him with a laugh.

“I NEVER would have guessed you guys were so strong. Well, okay, I knew you were strong, and maybe I coulda guessed Sans was strong too, he just never put effort into anything… but dude. You’re both forces to be reckoned with. I don’t know of anyone who’s ever summoned their own… I dunno, pet? And like, that’s an extension of your soul, more or less, and it’s just so cool…!”

“Nyeh heh,” Papyrus laughed, then winced as he rubbed his side. “Mine is… definitely very cool. But my brother… doesn’t like his much. Of course! He! Doesn’t like fighting at all, and his are so… intimidating, I don’t blame him. Not really. I’m sure if he just worked on using them in lighthearted, friendly skirmishes perhaps their demeanor would change!”

But you said yourself he doesn’t fight. I think he only used them today because Undyne might’ve hit him.

“…Yes…” Papyrus said, going oddly cold. His companion crept over to nuzzle him, then loped over to where his brother dozed. They watched as the creature circled a few times, and Papyrus looked ready to yell again as it picked his brother up gingerly in its teeth—then curled up and nestled him against its chest.

“Sorry, I just…” Undyne trailed, watching the scene unfold. “Oh my god, that’s super cute. Looks like even your attacks care about your brother.”

“You know, I think I’ll keep it after all,” Papyrus mused, stroking his chin. “It’s nice to have someone else looking after him, even if that someone is a sixty-foot-long skeleton dragon thing.”

I wonder what Sans’ attacks would look like if they were more than just skulls,’ Frisk wondered, and Papyrus shrugged.

“Something we will likely never find out. Sans is not so easily inspired by cool animes,” he replied, “or, anything at all. But one giant dragon thing is enough!”

“No way, you need like, A DOZEN OF ‘EM!” Undyne yelled. Papyrus began a counterargument, and Frisk laughed at them both. They glanced back at Sans, who seemed unaware he had a protector as he slept; the special attack had folded its forelimbs around him and rested its head on the grass, luminous eyes watching the world go by curiously.

Monster magic really was a strange thing, but it was wonderful too, and they wouldn’t have it any other way.