Sans had been working on the machine all evening. The clock read 12 AM, the temporal-meter was up to twenty-nine time-lines, and the photon readings were finally dropping. Sans hated working so long but lately the increase in the number of time-lines was weighing on his mind.
Something was causing their world to reset constantly. Sans had a million thoughts on what it was, but without anything definite it was all gut feelings and hunches. So, he focused on fixing the machine and getting Papyrus and him out of this time loop and back to their own world. To Sans, the more time-line anomalies they found, the less the world around them seemed to matter. The idea that he might have had the exact same spaghetti dinner with Papyrus for the 29th time in a row made it feel so inconsequential.
Thankfully, the core of the machine was cooperating with him right now. It was getting blacker and blacker as the night rolled on. It still needed to be darker yet for the machine to be operational, but the photon count was steadily approaching zero.
Filled with relief at the dropping number, Sans relaxed in his chair. He was drained from his work on the machine and allowed the drone of the machine to lure him into a half-sleep. He was interrupted only by the rustling of some leaves and the sharp scent of mustard. When he opened his eyes, he thought he caught a glimpse of a yellow flower which quickly vanished.
Still in a dream like state, Sans only thought "mustard been my imagination, heh." before finally falling into a dream about the last spaghetti dinner in this world he'll have with Papyrus tomorrow.
Sans awoke in his room to the symphony of his own snoring. The work on the machine felt like a dream and he didn't remember teleporting back to his room after he finished it last night. It just felt too real for him to believe it was anything else. He was sure the machine was almost operational last night, and decided to tell Papyrus the good news. The world went dark.
In an instant, Sans was standing next to Papyrus.
"'sup bro?"
"GOOD MORNING BROTHER!" Papyrus turned around and stopped stirring the pot of spaghetti he had cooling on the stove.
"I, MASTER CHEF PAPYRUS, AM TRYING A NEW BREAKFASTY INSPIRED SPAGHETTI DISH FOR THIS MORNING'S MEAL!"
"Breakfetti spaghetti? Is it even pastable to combine the two?"
"WELL SANS, YOU SEE I FIRST…" Sans smirked as Papyrus caught onto the pun.
"SANS!"
"Seems like it will be just as difficult as it was to fix the machine." Sans winked.
"YOU FIXED IT? WOWIE!"
"Yeah bro. I'll meet you in the lab."
The world went dark, and Sans was back in front of the machine. It was broken. Destroyed beyond what he could fix. There was no hum of the photon reader. The core of the machine was cracked in several places and a faint glow could be seen from its center. The temporal-meter was still working and counted the number of time lines. Sans saw "30" on the display, and his eyes went as dark as the core of the machine was in the last time-line.
He might have fixed the machine from this state before in alternate time-lines, but try as he might Sans could now barely remember what happened in the last time-line. All recollection of the previous time-line had vanished, wraith-like and ethereal. He had only impressions and deja vu left.
"SANS?" Papyrus walked into the lab. "NYOH HO HO! WHAT HAPPENED TO THE MACHINE? YOU MADE IT EVEN WORSE!"
Sans turned around, smiling just as he must have done 29 times before.
"heh, oh that? i was just kidding bro, heheh."
"NYEH HEH HEH! I SEE! EVEN YOU CAN COME UP WITH A GREAT JAPE WHEN YOU ARE PUTTING YOUR BACK BONE INTO IT! HEH HEH HEH NYEH!"
"SANS, DO NOT WORRY OVER THE MACHINE. FOR I, THE GREAT PAPYRUS, WILL BE HAPPY JUST BEING HERE WITH MY COOL BROTHER AND FRIENDS! SO FRET NOT AND LET US ENJOY THE BREAKFAST SPAGHETTI I HAVE PREPARED. THEN WE MAY WORK ON THE MACHINE... TOGETHER!"
"heh, no that's alright bro." Sans looked over at the display. "thirty is just an excessive number." He covered the machine and display with his lab coat.
"welp, i'm going to grillby's. papyrus, do you want anything?"
"YOU'RE GOING IN YOUR SLIPPERS?" Papyrus started looking around frantically for footwear that wouldn't go soggy outside in the snow.
"heh, no problem. i know a shortcut" The world went dark; Sans had left.