Watching Sans and Papyrus spar was always an exciting affair for Frisk. While Papyrus was much more liberal with his powers, Sans rarely used his- the only times Frisk having seen the older brother's magic being when there was true danger or he lost his temper, both situations were few and far between. Even with Papyrus's casual use of magic and frequent mock fights with Undyne, Frisk found that he only went all out when fighting Sans.
The ruined terrain was proof of the destructive capabilities of their magic- the three of them had trekked a little ways up Mt. Ebott to avoid destroying anything important- large furrows were carved into the ground and trees had been snapped clean in half. What little snow that had clung to the ground despite the warming spring weather was now blown away or mixed with dirt into a slushy mud.
Papyrus cackled and launched another bone at his brother, Sans stood across the clearing they'd chosen with one hand in his pocket and the other raised to summon a bone attack of his own. The two attacks met mid-air, a horrific crack resounding through the area as Papyrus's attack splintered in two, Sans's bone creaking as it bent and fractured, before both disintegrated as fragments blew outward from the collision and new bones were being summoned.
Right eye glowing neon orange, Papyrus sent a barrage of smaller bones at his brother, materializing a larger, sturdier one in his hands and bolting forward with long strides. Sans skillfully deflected the assault with a effortless flick of his hand, the bony appendage covered in a blue glow that matched his left eye, gaze tracking Papyrus as the taller skeleton sent out another wave in an attempt to distract Sans from his rapid approach.
But Sans only smiled easily, closing one eye and shoving both his hands into his pockets, dodging instead of deflecting, and moved steadily away from his brother. He wove around bones like it was nothing, not a single attack coming close to even grazing him.
"SANS!" Papyrus shrieked in frustration as he found their placement in the clearing flipped, "HOLD STILL AND FIGHT ME LIKE A REAL SKELETON!" With an angry lash of his arm another round of bones were sent ramming up through the earth on a fast path toward his opponent.
"Eh, since when do I follow orders?" Sans said with a nonchalant shrug, loud enough for Papyrus to hear over the sound of bones rending the earth, "Why would I start now?" He finished, eye pulsating yellow and blue as a gaster cannon flew to hover in front of him, opening its maw and releasing a laser blast that shattered through Papyrus's oncoming attack a second before it could reach him and continued blazing towards its target.
Papyrus rolled out of the laser's path and recovered quickly, lurching into motion in an attempt to get close to Sans once more. The shorter skeleton seemed content to let him draw near, starting again on dodging and avoiding when Papyrus swung his bone like a club, making the brothers appear to be locked in a deadly dance- Sans leading Papyrus in circles around the clearing.
Watching with rapt attention from the sidelines in the "bone-free zone," which was a neatly drawn rectangle- courtesy of Papyrus- on the very edge of the designated fighting space, Frisk marveled at how fast the skeleton brothers were. Their eyes had a hard time tracking Sans as he sporadically used small jumps of teleportation whenever Papyrus managed to get a little too close, and Pap moved with more grace and calculated technique than anyone usually gave him credit for.
Finally there was another sharp sound, Sans using his glowing hand to catch the bone Papyrus was swinging at him, arm shaking under the force Papyrus put into the blow, snapping it like a twig in his grasp with the aide of his magic. The younger brother growled and swung out a leg, Sans hopped over it but was thrown off balance when Papyrus changed gravity on him mid-jump.
"AH-HA!" Pap cried triumphantly as Sans landed on his back. His victory cry was cut short however as he was dragged backwards at lightning speed, like an invisible force had grabbed him around the waist and yanked him away. He went careening into a tree, knocking it over with a loud yelp, the trunk buckling under the force of Papyrus's backward momentum, snapping with a deep, creaking groan that ominously echoed off the mountain.
Sans sat up with an amused huff, leaning back on his palms and watching Papyrus try to pick himself out of the mess of splintered tree, raving all the while about bark in between his bones.
"I DEMAND A REMATCH!" Papyrus yelled, sounding not at all put out and more than a little excited, stumbling out of the hazardous pile of branches and pine needles toward Sans, still pulling bits of bark and wood from his clothes and joints.
"Nah bro," Sans sighed, letting his eyes slip closed, "You wore me down, I'm bone tired. Besides," He continued slyly, letting one eye crack open, "Looks like you're all bark and no bite!" Frisk giggled and took this as the signal that it was safe to leave their little rectangle, smiling as they trotted over to the brothers. Papyrus, despite his loud squawking about horrible puns, held out a hand and hauled his bother to his feet- lifting him clear off the ground for a moment in his enthusiasm.
"THAT WAS ABLSOLUTELY DEPLORABLE I DON'T KNOW HOW I STAND YOU." Papyrus huffed, marching off toward the path they'd taken up the mountain. Sans just shrugged and ambled after him, Frisk's hand swinging playfully in his, content to let his brother gain ground before noticing how far apart they'd gotten and come running back.
"So kid, how was the show?" Sans teased, looking down at the child beside him. Frisk practically tore their hand from his, throwing their arms to the sky in their excitement.
"It was amazing!" They exclaimed, smiling widely at the two brothers, "You guys are so cool! I wish I could do magic like you two!" Blue rushed to Sans's face in a skeletal blush, his expression startled and modest, while Papyrus bellowed out a laugh, gloved hands resting on his hips regally.
"OF COURSE, HUMAN! THE GREAT PAPYRUS IS THE COOLEST OF THE COOL, AND SANS IS PRETTY NEAT TOO! IT'S NO SURPRISE YOU ENJOYED YOURSELF!" He yelled with conviction, looking exceptionally proud of himself. Frisk nodded in agreement, hopping over to Papyrus and reaching their hands up eagerly with breathy giggles, making grabbing motions with their fingers.
Papyrus instantly recognized the wordless request to be held and happily lifted Frisk under the arms to settle them on his armored shoulders, the child's stubby hands resting on his skull. Sans snorted, struggling to hold in a chuckle at how easily Frisk could get Papyrus to do what they wanted- not that he was really any different, but he at least tried to look like he wasn't wrapped around the kid's finger.
They continued their walk home, conversing and joking easily with one another the entire way down the mountain and into town. People living in their neighborhood were all too familiar with the skeleton brothers and their human ward and many paused to wave- gestures Frisk and Papyrus returned enthusiastically while Sans gave muted nods in acknowledgment.
"HOW ABOUT THIS ONE: 'WHAT GETS WETTER THE MORE IT DRIES?'" Papyrus asked as they approached the house. Frisk 'hmm-ed' in thought, hunching down to avoid bonking their head on the doorjamb. They snuck a look at Sans and received only a sly side glance and silence in return. They were on their own for this one then.
Toriel appeared in the kitchen doorway upon hearing the trio enter the house, "Oh! Just in time, dinner is almost ready." She smiled, drying her hands on a dishtowel. Frisk sat up abruptly as a thought dawned on them, interrupting Papyrus and Sans's apologies about not helping make food with a dramatic gasp of revelation.
"A towel!" They cried, leaning over Papyrus's head to try and look at him upside down, giving his skull a soft pat.
"What about a towel?" Toriel questioned, equally confused and entertained as Papyrus laughed heartily and congratulated Frisk on figuring out the answer to his riddle, gently plucking the child from his shoulders and setting them on the tiled ground.
"Pap and Frisk have been giving each other riddles lately," Sans answered, swiftly swiping the pan Toriel picked up before she could clean it, "also you've done enough let us do some of the work," He shooed with a smile that Toriel easily returned, fondly laying a soft hand on his shoulder. Behind them, Frisk and Papyrus snickered at the table, stage whispering "Sans working? Can you imagine?"
Sans shot them a biting glare behind Toriel's back, prompting Frisk to clear their throat and settle down- though a small smile still clung to their expression. "Alright Pap," They said to get his attention away from teasing his brother, "'I crawl on the Earth and rise on a pillar. What am I?'" Frisk asked sagely, looking to Papyrus expectantly. The skeleton cocked his head, eyes narrowed in concentration and fingers drumming dully on the wooden dinning table.
"IT'S NOT A KIND OF BUG IS IT?" He asked uncertainly, glancing at Frisk beside him. The child shook their head with a closed-lip smile, short hair swishing into their face with the motion. Papyrus huffed and returned his stare to the table, focusing on its surface like he would find answers written in the wood-grain texture.
After a few minutes of silence during which Sans cleaned and Papyrus contemplated the new riddle, the oven timer dinged- signaling that Toriel's dinner was ready to eat. The mis-matched family chatted over their meal, Toriel asking about how the day was spent and receiving an enthusiastic- if not a little embellished- retelling of the skeleton brothers' sparing session from Frisk with the occasional commentary from Papyrus and Sans.
The relative peace was shattered though when Papyrus suddenly slapped his hand down harshly, clipping the side of his plate and sending lasagna flying into the side of Sans's skull while he was mid-bite, comically knocking the bit of food from his fork and leaving him stunned with his mouth still slightly open.
"A SHADOW!" The taller skeleton screamed, giddily turning to Frisk with a huge smile, unaware or uncaring that his brother was now covered in pasta. Frisk clapped their hands over their mouth, shoulders shaking with poorly confined cackles as Sans slowly turned his head to look at Papyrus- the lasagna sliding from his face and smacking onto the floor with a wet sound.
After a a brief moment Toriel too brought her hands up to her face, an ungraceful snort breaking whatever composure Frisk had scrapped up and sending the child into a howling fit of laughter that triggered more giggles and snorts from Toriel. Papyrus glanced between them, confused.
"WHAT?" He asked, looking to Sans for explanation only to find his brother staring at him with a stiff smile and lasagna sauce covering half of his head. "SANS! YOU'RE SUPPOSED TO EAT THE LASAGNA, NOT WEAR IT!" Papyrus chastised with a serious frown. Sans blinked slowly, his grin growing larger.
"I dunno bro, I think it makes me look kinda saucy," He said with a wink, making tears form in Toriel's eyes as she laughed even harder.
"OH MY GOD YOU'E IMPOSSIBLE!" Papyrus groaned loudly, leaning back in his chair and covering his face with his hands.
"You mean im-pasta-ble?" Sans asked quickly, grin getting even larger at the screech his pun elicited from his brother and the added wheezing it tore from Toriel and Frisk.
"Okay but seriously," Sans continued, both of his eyes sliding closed, "you should try it!" His eyes snapped open, blazing blue, and Papyrus's head was shoved into his food. Papyrus squawked and flailed his arms while Frisk and Toriel froze, their laughter dying instantly. Raising his head from his plate with a squelch, Papyrus gently pulled a bit of noodled and cheese from his eye socket, giving an uneasy, full-body shiver at the sensation as he did so. Everyone was silent, watching Papyrus hold the noodle between his forefinger and thumb like it was going to bite him with a vaguely horrified look on his face.
"Hehehe," Sans was the first to giggle lowly, head shrinking down into his hood, before exploding into a full-blown roar of laughter. Papyrus frowned and flicked the noodle at his brother, which only made Sans laugh more, managing to shout a short "Ew dude!" between fits. The rest of them joined in too when Sans nearly fell out of his chair, tears streaming down his face.
"WHAT ARE YOU LAUGHING AT HUMAN?" Papyrus teased, turning to grin mischievously at Frisk, grabbing a handful of lasagna and throwing it at them. With a loud yelp, Frisk was able to duck in time, the lasagna harmlessly hitting the wall behind them and slopping to the floor. Grinning, Frisk peeked over the edge of the table, reaching for their own plate of food.
"Oh! No no no!" Toriel interjected in alarm, "That's enough!" She cried standing up and grabbing Frisk's plate before they could retaliate. She looked at the three in front of her, noting the small flecks of sauce that had made their way onto Frisk's face and how messy the two brothers were.
"All three of you are taking a bath," She announced in what Sans liked to call her 'I-used-to-be-a-Queen' voice voice, "Go to your rooms and get cleaned up." Sans and Frisk deflated visibly, grumbling and following Papyrus- who practically shot up the stairs- at a much slower pace.
"And don't you dare get any food on the carpets!" Toriel called after the trio, receiving vague sounds of confirmation in return to show that she was heard. Taking one last look at the kitchen, Toriel sighed at the mess. A small smile snuck its way onto her face though, she couldn't really bring herself to be mad, it had been rather hilarious after all. She sighed again, though this time it was a more contented noise, and began the process of cleaning the dinning area, listening in amusement to the sounds of Sans being chased around upstairs and finally forced into a bath.
I dunno why but I picture Sans as someone that needs to be forced to bathe (sometimes he does it just to be difficult tho). Also this was completely directionless, when I started the only thing I knew was that I wanted to write some Undertale. This all just HAPPENED.