Hello Readers! This is my first foray into Undertale fanfiction and I'm a bit rusty (so be gentle (8o8) ).

WARNINGS: Some harsh language (especially from Sans), Alcohol(?) abuse. Talk of suicidal thoughts. Probably some angry smooching. Definitely angst and major character death.

SPOILER ALERT: Basically every conceivable spoiler might rear its head in this story, since the premise is that some entity is screwing with the timelines and garbling them up. In fact, to get the most out of the story you'll probably want a very intimate understanding of the Undertale MetaGame including the neutral, pacifist and genocide runs.

DIFFERENCES FROM POPULAR CANNON: Female Frisk. Older Frisk (perhaps around 16-17 y/o?) so all the monsters are scaled up to the same relative heights of the sprites in game. This means that Sans is just under 6 feet tall and rather menacing.

May also delve into some popular AUs (possession, underfell, bromalgamate etc.)

In summary: All aboard the feels train! Choo Chooooo~!

-WHATEVER CAN HAPPEN WILL-

CHAPTER 1- RESET

Sans shot bolt upright on the couch. There was a sickening sensation of disorientation that crashed over him in waves and he knew that if he'd had guts he'd be puking them up right about now.

Heavily, he tried to roll his bones off the lumpy cushion and stand but the nausea was too much and he ended up sprawling onto the floor.

"paaap-?" He moaned weakly, feeling gravity shift like he was using his blue magic. Images began flashing through his mind faster than he could make sense of them, juxtaposing and branching apart and coming together and falling apart... Becoming dust.

No. God no. Not again...

"p-aaaap?" Sans felt the fear next; crawling on his back and sinking into his marrow. They had been there. On the Surface. They'd been free... and... and...

"BROTHER? IS THAT YOU? AWAKE ALREADY?" Papyrus' loud voice filtered in from the kitchen. It's grating quality soothing to Sans' ears nonetheless. Whatever new Hell he'd just woken up into, at least his brother was safe. For now.

Papyrus leaned out of the kitchen, clutching a pot of boiling water and spaghetti to his chest (he didn't seem to notice how it was singing his Battle Body chestplate). The lanky skeleton's expression flickered from its regular enthusiastic grin through enthusiastic alarm and quickly into enthusiastic consternation at finding his lazybones brother on the floor.

"SANS. I'M AFRAID YOU'LL HAVE TO WALK TO THE KITCHEN LIKE A NORMAL MONSTER. IF, YOU WANT ANY OF MY DELICIOUS SPAGHETTI, THAT IS. NYEH HEH HEH!" Papyrus was stirring the scalding water so vigorously it was sloshing out the sides of the giant pot.

"you got me." Sans pushed down the last of his lingering queasiness and fell back on his favourite self-defense mechanism. "but the smell of your cooking just had me..."

"SAAAAANS!" Papyrus started stirring so hard that full, semi-cooked spaghettos were flying out of the pot.

"floored."

"BROTHER I DISOWN YOU!" Papyrus cried as he swept back into the kitchen, smiling despite himself.

...

...

Slowly, carefully, Sans pushed himself out of his prone position and rested awkwardly against a lumpy armrest. Despite being a skeleton-monster, his magically-chubby belly sat heavy on his frame. Sans drew a bony hand across his face and then wiped himself off with well-used handkerchief when he found that he'd been sweating uncontrollably.

Mustering what was left of his determination, Sans pulled himself back up onto the cushions and felt himself sink into the couch's green polyester embrace. Winded from even that small exertion, he decided that what he needed was a good deal less Grillby's and a good deal more exercise. He felt tired at the prospect.

However, he was avoiding the issue. The human, that damn FREAK had done it again. Despite its promises and friendship and mercy. After doing everything perfectly right it still wasn't satisfied. WHY?! What did it want? Sans tried to remember how many times he'd awoken on this same couch, to the quiet tune of Mettaton re-runs and the joyful whistling of his brother cooking as if nothing had happened. How many times had that thing RESET?

He was alarmed to discover that he'd lost count.

"hey paps. going for a walk, okay? would you pack up my spaghetti for later?" Sans got up and slouched towards the front door, the time-sickness already fading.

"VERY WELL! BUT REMEMBER. LATER WE'RE GOING TO GO RE-CALIBRATE THE PUZZLES. I HAVE A FEELING. THAT TODAY WILL BE AN IMPORTANT DAY."

"i know." Sans replied quietly and stepped out into the cold in nothing but his usual blue hoodie, track shorts and fuzzy slippers.

...

In the quiet of the house, Papyrus stopped stirring and stared at the closed front door. He felt his gloved hand shaking around his wooden spoon so he tightened his grip to make it stop. There was that feeling again. Like he had just been somewhere else, doing something else. Something happy... he thought? He'd felt so happy.

He had been about to continue his cooking when he felt a shiver go down his spine and to his surprise he discovered that he couldn't move, not even an inch.

A low whine escaped him as he felt his soul clench where it lay nestled inside his ribs. He'd wanted to call out for his big brother, but he couldn't even do that. Then, to Papyrus' mounting horror he became aware of a presence in the kitchen with him. Something dark shifting in the peripheries of his vision.

He tried calling out again for Sans but this time he couldn't even muster so much as a whimper.

.

.

.

.

Sans didn't bother with taking any of his shortcuts today. He knew he didn't have to hurry. Besides, it felt kind of good to get from place to place one foot at a time. Tiring, but good.

He knew he had a good while before THAT FUCKING HUMAN stumbled out of the Ruins so Sans took a detour into Grillby's. Sans may not have been as tall as his brother, but he was still big as far as monsters went. At a bit under six feet to the crown of his head and sturdily built, he had to angle himself to fit through the bar's door. His earlier resolution to eat less greasy food crumbled into dust as he settled himself onto his usual stool.

dust... fuck.

Apparently picking up on Sans' distress, Grillby slid a bottle of ketchup towards him across the well-polished bar. Also apparently, Sans was looking worse than he thought because the ever-astute barkeep also presented him with a small shot of some hot mustard, the hard stuff.

"thanks, grillbz." Sans gave him his patented grin in appreciation, to which Grillby simply shrugged and pushed his spectacles further up his non-exisetent nose.

The bar was fairly empty right now (as it always was at this point in the timeline) since the royal guard-dogs were all off sniffing out trouble in the mountains. The other patrons seemed relaxed, however. At peace with their lots in life and content to while away the unchanging ages in good company. Sans envied them a little as he tossed back his hot mustard and let the warming numbness stop the overactive gears in his mind from grinding quite so painfully.

He had been halfway through his second bottle of ketchup and his first burger (so he'd caved, alright?)when he heard it.
A shout.

Papyrus' shout.

The lights in Sans' eyes contracted to pinpricks in fear. That had never happened before! Sans nearly fell out of his seat on his way to the door, knocking over the dogs' poker set-up in his panic.

"Hey Sans buddy, what the matt-" The flytrap monster was cut off as the door slammed closed behind him.

The wind outside had picked up noticeably and he could feel the little crystals of blown snow glancing off his exposed bones. Not for the first time Sans was glad he couldn't feel temperatures. It was strange, though. He could have sworn that this blizzard wasn't due until at least tomorrow.

The big-boned skeleton stood perfectly still on the quiet, snow-scoured streets, all senses on high alert. At least as alert as they could be through the haze of monster-alcohol. Papyrus was right, Sans thought sullenly. He really was turning into a slob.

Just as Sans was about to attribute the shout he'd heard to his drunken, stress-adled mind he heard it again. This time, however, he was able to recognize it as a shout of... joy? It was coming from the direction of the mountains and the Ruins.

Feeling rattled, Sans ducked behind the Librarby and into one of his shortcuts. The one he knew would take him straight to the big stone doors of the Ruins.

They'd been opened already. Little wings of snow-bare rock were visible where the double doors had swung outwards, though they were quickly being filled in by the mounting blizzard. Side-stepping, Sans re-appeared near Papyrus' electro-maze and was shocked to find not two, but three sets of footprints already leading through the maze, one dainty, one obviously his brother's and a third padded and overlarge.

what?

Sans flitted from space to space, feeling the drain on his magic keenly as he watched with growing horror as he saw the evidence of the changes in the timeline.

The snowman had been untouched, Alphys' tile puzzle had settled on a genuinely random puzzle which had apparently been solved. The snow dodecahedron near the 'ball' game was now obviously an octadecahedron, and Papyrus' super-deadly human trap had actually been sprung. (Although the annoying dog was still dangling from its rope, seemingly as confused as Sans was).

Finally, Sans stumbled back into Snowdin, practically collapsing from exhaustion. In fact, yes. He did decide to collapse from exhaustion as he dropped to his hands and knees and felt utterly blind-sided. It was all different. It was all new.

Before he could stop himself, Sans felt a manic grin draw at the corners of his mouth. He hadn't felt so alive in years! He started laughing, then he started crying and then he started hiccuping as he tried to do both at once, fairly certain he was finally losing his mind.

"Hey there. Are you alright?"

Sans was dragged out of his internal spiral by a soft, timid voice. He knew that voice. It was the voice that haunted his worst nightmares, and his best ones. Frisk.

"SANS? WHAT ARE YOU DOING? BUILDING A SNOW FORT WITHOUT ME?"

Sans looked up to find the human girl standing timidly before him, daintily posed with one hand outstretched as if to help him up. Despite his exhaustion, he slapped it away and struggled to his feet without assistance.

Who did the human think she was kidding? They both knew that the moment Sans let down his guard was the moment he'd find a knife between his ribs.

"THAT WASN'T VERY NICE!" Papyrus chastized as he drew closer. "DON'T YOU KNOW HOW TO GREET A NEW FRIEND?"

Sans had been about to make a biting retort but Papyrus' words made it stick in his throat.

This was wrong.

Despite all evidence that this human child was as cold-blooded a demon that had ever walked the Underground, Sans was surprised to discover the first hint of tears brimming in their young eyes. Though perhaps... not so young? Sans gave the human a long, appraising look up and down. Though she was still young and frail-looking, the girl was nearly as tall as Sans' chin, and that was even as he tilted his skull back menacingly. He could even see the first curves of womanhood through Frisk's formless striped sweater.

The throught briefly crossed his mind that perhaps this was Frisk's actual age, what with all the endless SAVES and RESETS.

"sorry, uh, bucko?" Sans stammered, his mental processing capacity thoroughly spent. He realized dispairingly that he had forgotten his palm-sized whoopie cushion at home, but under Papyrus' enthusiastically disapproving glare he had no choice but to stick his hand out to shake.

"real... pleased to meet'-"

"PBBBFFFFFFFFFTTTTTHTHHHHBBBBBTTT...PBFTHT... Poot."

Both Sans' and Papyrus' eyesockets went wide at the rude noise, though for very different reasons. Frisk threw her head back with laughter, a sound that Sans had never heard her make before.

"HUMAN. THAT WAS..." Papyrus managed.

"Well done, My Child." A new voice, tinged with suppressed laughter preceded the newest change in the timeline. Sans knew that voice too, and not just from his endless knock-knock joke sessions.

Lo and behold, Toriel herself padded up to the group and placed a hand on Frisk's beaming head (apparently having forgotten Sans' rudeness earlier). Tori's silky, white fur rippled in the rising wind but she didn't seem to mind the cold, even though she had ABSOLUTELY no business being here.

"have we... met before?" Sans asked, knowing even as the words came out of him mouth that he was reading from the wrong part of the script, so to speak.

Toriel's big, ruddy amber eyes opened a little wider in recongition and a glad smile spread across her muzzle. Despite everything, it still warmed Sans' heart to see it.

Before they could make their proper introductions, however, Papyrus threw a bone in things and announced: "THE HUMAN CHILD IS COLD. AND SHE OWES ME A DATE. CAN WE TALK MORE AT HOME? OVER SPAGHETTI?"

There was a general agreement and Sans found himself wandering after the group of his friends (and not-so-friend) towards their home. He was still reeling from the fact that Papyrus and the human had already fought and he hadn't even been there to help the human over that last, gigantic bone in Papyrus' not-so-special attack with his blue magic. He hadn't been there to watch over his brother, the one reason he hadn't jumped into the Hotland lava years ago.