Sans had been pacing for what felt like hours. The rhythmic shuffling of his slippers hitting the floor was the only thing he allowed to break the silence of the house. Any other noise might make him have a panic attack at this point. It was all he could do to concentrate on his steps.

Shff shff shff shff!

He forced himself to breathe with them. In on the first step, hold on the second step, out on the third step, hold on the fourth step. In. Stop. Out. Stop. In. Stop. Out. Stop. It gave him something to concentrate on when his thoughts started swimming too much.

He hated it when Papyrus did this - came home late from practice. He hadn't answered his phone in hours, and neither had Undyne. It was dark outside, they had no reason to still be practicing - though he supposed it was always pretty dark in waterfall. If they didn't pay attention to the time they'd never really know it had gotten so late. But they should still know time had passed, too much time had passed.

Granted, this wasn't the first time Papyrus had come home late - though this was definitely the latest he'd ever been. But the fact that he wasn't answering his phone made Sans think something was wrong - horribly wrong. A feeling of dread and foreboding crept down the back of his skull, making his spine crawl as if he were covered in spiders. Or maybe that was just his nervous sweat. His hands shook even as he wrung them together, every piece of his body a fidgeting, nervous mess.

Logic told him he had no reason to be this upset. Nothing ever changed in the underground - being hit by a cave in or falling stalactite was as likely as finding a human. And while crime was possible most monsters were too busy dealing with their own problems to cause them for others. The news was always calm, the most noteworthy things to happen were lost pets and the occasional bit of vandalism that the punks in Snowdin forest managed to cook up.

And suppose that one in a million chance happened that someone tried to hurt Papyrus? Well his brother was strong. Strong enough to train with the Captain of the Royal Guard! And while kind hearted and a bit naive, Papyrus was still more than capable of defending himself.

Logically, there was no reason for Sans to be this terrified. In fact, there was no reason for him to worry at all.

But what he was feeling now was anything but logical. Crippling anxiety, borderline paranoia, bone-shaking terror. He could reason himself through it all he wanted, it still ended the same. Something terrible must have happened. Papyrus was either dusted or dying. He hadn't been there to protect him. Hadn't been there to shield his brother with his own meager HP. To stop an attack with his own fragile bones. He was so sure, so sure his brother was dead. So sure that he was too terrified to go outside, to look for him, to confirm his worst fears. Every time he reached for the door he shook so much his bones rattled. His breathing hitched in his throat, his chest got tight.

A knock suddenly sounded at the door, startling Sans so much he let out a shriek. He was breathing twice as fast as his own footsteps. His vision suddenly pitched, and he realized he'd managed to trip over his feet.

"BROTHER? IS EVERYTHING ALRIGHT IN THERE?"

"Y-yeah dude," his voice was hoarse with relief as he nearly leaped for the door, "Everything's fine!"

It took everything he had to cross to the door slowly, concentrating hard on smoothing down his breathing and frantic heartbeat. The pinpricks up his spine were still there, but relief was already starting to wash over him.

As casually as he could manage, Sans opened the door.

"T-took you long enough, bro."

Papyrus loomed over Sans, nearly twice his height. He rubbed the back of his head somewhat embarrassedly, a grin plastered across his features, "INDEED! I WAS QUITE UNABLE TO LEAVE AT THE REGULAR TIME. UNDYNE NEEDED SOME ASSISTANCE!"

Sans stepped aside, letting his brother into the house. He couldn't help the bitterness that glanced across his voice, "Still could've answered your phone, dude. You had me… uh…" his mind worked shakily for a second, "... uh… totally rattled?"

Worst pun ever.

Sans frowned, watching a shadow pass over his brother's normally enthusiastic face. He made no comment about the pun whatsoever. The familiar tightness worked its way back into Sans' chest.

"Uh… bro…?"

"YES, MY PHONE DIED WHILE AT PRACTICE," he fidgeted a bit with his hands, "I REALLY DO APOLOGIZE SANS, I KNOW YOU WORRY GREATLY. ITS JUST… WELL…"

Sans attempted to keep his features worked into a lazy smile, but his nearly abated panic was slowly growing again. This wasn't like his brother at all.

"S-something happen at practice?"

Papyrus sighed, "SORRY, I DON'T WANT TO WORRY YOU FURTHER. BUT I SUPPOSE YOU SHOULD KNOW…" Papyrus took another breath as if to prepare himself, "UNDYNE COLLAPSED AT PRACTICE TODAY."

Sans' breath caught in his throat, and though he tried to keep his face steady, something in his expression must've broke. Papyrus brought a hand up, a look of concern etching its way through his features.

"WAIT WAIT! DON'T WORRY, SHE'S FINE NOW! THERE'S NOTHING TO WORRY ABOUT-."

"Why did she collapse?!" Sans exclaimed, exasperation and panic making it's way into his shuddering voice, "She's Undyne! That doesn't just happen to someone like her!"

"BROTHER CALM YOURSELF," Papyrus sighed, "I REALIZE IT IS VERY SHOCKING, BUT YOU MUST UNDERSTAND, SHE IS PERFECTLY FINE NOW."

Sans took a breath and held it, counting slowly to ten, practically willing his heart to slow its frenetic beating. So something had gone wrong. Not what he'd expected, but for once his panic actually meant something. He couldn't stand it. Finally he let out his held breath and took a few deliberately slow gulps of air. Breathe. Breathe.

"What happened?"

Papyrus gazed down at his brother, gauging to see if he was really calm enough to continue. Though he supposed leaving the conversation as it was now would only make him worry more. He never did quite understand why his brother worried so much - and he wondered if even Sans himself knew. But there was no helping it. All the reassurance and inspiring confidence in the world couldn't convince his brother that he had no reason to fear. Papyrus absently wondered if it had something to do with how weak his brother was. Surely a monster with such low attack and defence would find the world a very terrifying place. Though Sans made no move to change any of this on his own.

"WELL WE WERE POUNDING THE TOMATOES FOR A MOST FABULOUS SPAGHETTI," Papyrus began, throwing a bit more confidence back into his voice, "AND IT WAS ACTUALLY TURNING OUT QUITE WELL! I HADN'T EVEN BURNT ANY OF THE INGREDIENTS YET."

Sans did his equivalent to raising an eyebrow at his brother. He was clasping his hands in his hoodie pocket to keep them from visibly shaking.

Papyrus sighed, "WELL… THAT WAS WHEN SHE… COLLAPSED. ONE MINUTE SHE WAS COACHING ME AND THE NEXT... SHE JUST… HUGGED HERSELF AND FELL OVER. IT WAS QUITE TROUBLING. SHE DIDN'T CRY OUT, BUT I COULD TELL SHE WAS IN IMMENSE PAIN. IT WAS ALL I COULD DO TO HELP HER INTO HER ROOM AND KEEP HER CALM. NYEH HEH… MY PRACTICE WITH YOU CAME IN HANDY, IT SEEMS."

Sans nodded quietly, his gaze shifting to stare at the floor thoughtfully.

"I GAVE HER WATER AND HAD HER LAY DOWN. SHE SAID IT WAS HER CHEST THAT HURT, THAT IT HAPPENS SOMETIMES. SHE'S SAID THE SAME THING ABOUT HER EYE SOMETIMES… THAT IT'S A REMAINING PAIN FROM WHEN SHE LOST IT YEARS AGO. BUT I'VE NEVER KNOWN HER TO BE IN A FIGHT WHERE SHE WAS SO SEVERELY INJURED ACROSS HER CHEST LIKE THAT. AND WHEN I ASKED SHE WOULDN'T ELABORATE."

Sans nodded again, his brow creasing slightly with thought and worry. A pain in her chest? And one that was so bad she was bedridden because of it. He didn't know Undyne like his brother did - they were good acquaintances at worst and meager friends at best - but in all the time he'd known her she'd never told any stories about an injury like that. And knowing Undyne, a battle that could cause such an injury would be one she would gloat over. Undyne wasn't exactly the subtle type.

"Did you call a doctor for her? Or at least get Alphys?"

"... NO." Papyrus sighed, his expression becoming more downcast, "SHE ASKED - WELL MORE LIKE DEMANDED - I NOT TELL ALPHYS. BUT I PROMISED I WOULD CHECK ON HER IN THE MORNING… TO MAKE SURE SHE WAS OKAY."

Papyrus gave a nervous laugh, his features settling back into their familiar light-hearted grin, "SHE WILL PROBABLY BE ANGRY THAT I'M CODDLING HER SO MUCH, BUT SHE REALLY WORRIED ME TODAY. I, THE GREAT PAPYRUS, CANNOT SIMPLY STAND IDLY BY WHEN SHE COULD BE IN DISTRESS!"

Sans did his best to put on a smile, "Good thinking bro. Heh… sounds pretty intense."

"IT WAS INDEED. BUT I DID REMEMBER SOMETHING WHILE WE WERE TALKING."

Sans' smile faltered a bit, "O-oh?"

"YES," Papyrus reached up a hand to rub the back of his neck, massaging a kink in the vertebrae that wasn't there, "WHILE SHE WAS TALKING ABOUT HER… HURTING… I REALIZED I HAD FELT SOMETHING SIMILAR BEFORE. IN MY NECK. IT'S NOT VERY OFTEN, SOMETIMES I GO WEEKS WITHOUT IT HAPPENING. BUT I GET A VERY SHARP PAIN IN MY NECK THAT IS QUITE DISTRACTING. PERHAPS WE ARE TRAINING A BIT TOO HARD? MAYBE WE SHOULD TAKE IT EASY FOR A BIT. UNDYNE WILL PROBABLY NEVER AGREE, BUT I WAS THINKING ABOUT BRINGING IT UP TOMORROW WHEN I WENT TO CHECK ON HER. PERHAPS I CAN CONVINCE HER TO REST A BIT."

Sans's breath caught in his throat again, and he felt as if his heart had sunk a few inches in his chest. But for the first time that night, he managed to hide it. His smile twitched but it didn't drop, and with his hands in his pockets as they were, Papyrus wouldn't be able to see them shaking.

"W-what? You kidding me bro?" Sans managed a shaky laugh, "You and Undyne over doing it? Come on, you're the toughest monsters I know! Though you're right, rest might be what she needs right now. Sounds like you got a solid plan going."

Papyrus beamed, happily soaking in the praise he'd received.

"BUT OF COURSE, I THE GREAT PAPYRUS ALWAYS COME UP WITH THE BEST OF PLANS! AND I AM INDEED STRONG. HOWEVER…" His brow furrowed a bit with concern and the previous grandeur in his voice once again slipped away, "I DO WORRY ABOUT YOU BROTHER. YOU ARE VERY MUCH WEAKER THAN I, AND FRAGILE. I WAS WONDERING, HAVE YOU EVER FELT SOMETHING LIKE THIS BEFORE?"

Absentmindedly, Sans slipped a hand from his hoodie pocket to grasp at his chest. His finger bones gripped the fabric, and his heart gave a twinge.