A/N: I'm back!

So today at school I basically did what I call 'Naruto-ing.' That is, pay attention until we were sent off to do our individual work and speed through while also trying to get everything right, then work on writing fanfics. Basically how I write my fics: just go back and forth between electronic and paper and transfer it all here when I get enough for a chapter or two, or just transfer it and edit it.

So not only did I write this, I edited most of it. And I'm posting a lot because I have nothing else to do and I wanted to start a fic with just a bunch of one- or two-shot and then some stories with five or so chapters. Might switch it to five-shots (is that a thing?) and fewer. I don't know.

I can make this a single story or a bunch together. It's all Undertale, so if you guys want me to try writing about a certain AU or story then let me know!

DISCLAIMER: I DO NOT OWN UNDERTALE OR ANY CHARACTERS MENTIONED! I ALSO DO NOT OWN ANY AU'S MENTIONED! I only own the storyline and any OC's.

NOTE: Frisk = non-binary. Mettaton and Napstablook = male. Monster Kid = female. Chara = virus/demon/I don't know. Don't like it then either deal with it or leave (AFTER READING AND/OR REVIEWING!).

Note No. 2: The story jumps right in. I had no idea how to explain it or anything. Originally it was going to be part of Sans' Secret and The Timeline Battle/War, but I changed my mind when it became more of a totally different idea and now it's a stand-alone story. THIS IS NOT A CONTINUATION OF THE SANS'S SECRET FIC! THIS IS A TOTALLY DIFFERENT STORY!

Note No. 3: Backstory: Post-Pacifist. Asgore still stays at the castle but Toriel has a new home in Snowdin. Frisk lives with Toriel and Flowey never revealed to anyone but Frisk that he was Asriel. Flowey lives with Frisk and Toriel. The barrier wasn't opened and the monsters (plus Frisk) stayed down in the Underground. Also the path to Mt. Ebott was blocked so no more Fallen Children... Gaster has returned and lives with Papyrus and Sans. Story start: Toriel and Frisk were at Asgore's and were coming back. Sans and Gaster were waiting up while Papyrus had his cooking lesson with Undyne.

WOW. Long A/N!

Enjoy!

Gaster went and poured two cups of coffee, his back to Sans. The former Royal Scientist paused, then turned to give Sans his coffee. "Hey, Sans," the tall skeleton said.

Sans blinked and took the coffee, mumbling "thanks" before draining it in two gulps. He yawned and glanced at the window. "Hey, Gaster, do you know when Frisk and Tori are gett-" his eye sockets widened. The white points disappeared, leaving the empty depth. "Gast-" Sans started coughing violently, so hard he knocked his chair over, spilling to the ground. He crawled towards Gaster, who stood by the counter, who was filled with DETERMINTION.

Sans fell to his hands and knees, blue jacket still wrapped around him. He gasped and coughed, pain blazing through his body. Then he felt a prick on his arm, and looked up to see Gaster pulling a syringe out of his bones.

His vision began tunneling. From a distance he saw Toriel and Frisk burst in, and then Tori yelling and Gaster yelling back.

"Sans!" He heard faintly. Frisk- oh, Frisk, the human child, oh, your genocide route was nothing compared to this!

Oh, god, it hurts, please stop the pain! It burns oh god stop it please, help me!

Sans heard his voice and dimly realized he was the one crying out, tears pouring down his face.

"Sans!" Frisk shrieked.

Sans curled into his side in a ball, crying, oh god it hurts what did Gaster DO?!

The last thing he saw was Toriel frantically calling someone and Frisk throwing their arms around him and Gaster roaring at his own phone.

Then everything went black.

_time_skip_

Pain. Fire through his bones. Then it faded and his body grew warm. He could feel a few things in particular; his soul, something cool gripping his hand, and... warmth. Not fire blazing in his body anymore, but a nice heat, so much better then the coldness he's lived through for years and years and-

Then his sense of touch faded and he passed out.

_time_skip_

Voices now. The warmth was back, and his soul, and the coldness gripping his right hand.

"Gaster, I told you, Asgore and Toriel are-"

"Alphys! You know what I told you!" Gaster.

"But you let Papyrus and Frisk in!" Alphys.

Papyrus. Of course. Sans recognized the cool skeletal hand clutching his own now, it was his brother's. Frisk mustn't be here right now, or they would be right near Papyrus.

"So when is he going to wake up? It's been-" Alphys had lost her stutter, as she always did while in her scientist mode. Sans could recognize that tone anywhere.

Gaster sighed. "His soul is stable and his magic is perfectly unaffected. There is no reason for panic."

Alphys literally growled. "You gave him the DT serum and injected him with pure DT! I really wonder why we all are panicking and everyone is crowding around downstairs?!" Sarcasm dripped from her words.

Sans suddenly moaned inwardly as his senses withdrew. *JUST LET ME WAKE UP!* he screamed silently.

_time_skip_

Taste. Hearing. Touch. Three out of five.

He knew this because he could feel someone pressing something to his lips; water. Then a minute later he heard the sound of... was that ketchup? Really? Why-

Oh.

It was Papyrus he heard earlier, arguing that "SANS SHOULD BE ABLE TO EAT WHAT HE LIKES! IF HE WERE AWAKE HE WOULD WANT KETCHUP SO TOO BAD IF THAT SCREWS WITH YOUR STUPID SCIENCE CRAP!"

And then he was eating ketchup. He laughed inwardly. Ketchup. After a second there was more water, then nothing as his senses faded yet again.

_time_skip_

Smell. Taste. Hearing. Touch. Finally, soon he would wake up! The darkness was depressing and he wished more then ever to be able to joke around with his brother and friends.

He smelled the usual scents of his room; with a sharp, clean sort of sting to it. Gaster and Alphys. Again with their stupid lab equipment?

Then it faded again. He wanted to punch something. *Let me wake up!* he screamed silently.

_time_skip_

Light.

Sans now saw the darkness getting lighter. Not by much, but enough that he almost started crying in relief. Not like him, but this was a special case.

And his senses came back. They didn't leave. Only his sight stayed just out of his grasp, slowly lightening the darkness as time went on.

Later he suddenly realized he could feel his whole body, not just the warmth and Papyrus' absent hand.

"GOOD MORNING, BROTHER!" Papyrus' voice suddenly said. Sans guessed he had just entered the room. "I DON'T KNOW IF YOU CAN HEAR ME BUT I'VE BROUGHT SOME OF TORIEL'S LOVELY BUTTERSCOTCH PIE. ITS QUITE DELICIOUS!"

Sans heard Papyrus move around awkwardly and sit to his right. A moment later, something warm touched his mouth. Papyrus was holding his right hand with his left and giving him pie with his right.

Sans struggled to move, to blink, ANYTHING. He gasped silently, then took a deep breath.

He concentrated on his right hand, the one that was clasped in Papyrus' hand. He strained and strained and-

Until, miraculously, Sans managed to squeeze Papyrus' hand before mentally collapsing with exhaustion.

Papyrus gasped and Sans heard the fork hit the ground. "Br-brother?" His brother whispered, not yelling for the first time in who know how long.

Sans felt Papyrus throw his arms around him, sagging with relief inside. The darkness was lighter, sure, but it was still an extremely dark gray.

He felt himself slip into sleep once again.

_time_skip_

Light.

Sans' eyes flew open and he sat up extremely fast, chest heaving.

Beside him, Papyrus whispered, "S-sans?"

Sans stared at the base of his bed, breathing heavily. Something was different. His eyes were wide, silent.

"Sans!" Gaster gasped from the other side of his room.

Fury filled Sans and he thrust an arm at Gaster. A Gaster Blaster appeared in front of him and fired, firing a blast bigger then he's ever summoned before. Gaster barely had time to teleport out of the way before the blast hit the wall and exploded out into Snowdin.

Sans froze as he stared at his hand. What-

"Sans, calm down-" Gaster began but Sans yanked the covers off his legs and stared at his very human, very NOT skeletal legs and feet.

"GastER I AM GOING TO KILL YOU!" Sans bellowed and leaped at the scientist - or tried to, at least. He more or less fell out of bed and face-planted on the floor. "YOU SON OF A-"

"SANS!" Papyrus yelled. He picked Sans up under his arms, holding him up in the air. "CALM DOWN!"

Sans was breathing heavily, and glanced up to see frosty white hair falling across his forehead. He still wore his usual black shorts and white t-shirt. His pink slippers were by the door and his jacket behind Papyrus' chair.

Sans let out a groan. "Gaster I swear, you better tell me what you did or I swear you're gonna have a bad time!"

Gaster swallowed. "I slipped a DETERMINATION serum into your coffee. You started changing right there. It was too fast, so I injected pure DETERMINATION into you."

Sans began struggling. "Paps, put me down-"

Papyrus set him down and immediately, Sans was grabbing his blue jacket and shoving his feet into his slippers. "BROTHER, WHERE ARE YOU GOING?"

Sans whipped around. "Away from Gaster."

He teleported away before Papyrus could grab him.

Sans stumbled as he reappeared in his lab, shocked at how easy his teleporting had been. He managed to move to the sets of drawers in his lab and braced himself against the shiny silvery counter.

A white-haired, pale blue-eyed boy stared back at him, about sixteen. He had Sans' blue jacket and his white shirt and even that hint of laughter in his eyes.

Sans stumbled back and sank to the ground with his back against the wall with his head in his hands. He couldn't do this, he can't go back-

He can't go back to his past. The machine is broken, he can't use it. That Timeline's gone anyways. He'd never get home. He was stuck here, and he had finally accepted himself as a skeleton and a part of this Timeline when that stupid Gaster had to go and change him back.

Sans buried his head in his arms. "Why, Gaster?" He muttered. "Why do you have to do this to me?"

After a moment, he curled up against the wall, pulling his jacket closer around himself.

Ending A/N: I probably shouldn't have put so much into one chapter.

BUT FUCK HAVING A FIFTY CHAPTER FANFIC I WANT A NICE 5 TO 10 CHAPTER FIC!

Also yeah. I don't own the cover but I found it online while looking for a good image of Human!Sans, and I don't know who owns it. I DO NOT CLAIM TO OWN IT! And also Papyrus will not become a human. And Frisk's not turning into a non-binary, bi-pedal goat-monster. Sorry.

If you have any special AU's you want in this for later on (hint, hint) then feel free to let me know and I will research them or figure out how to distinguish future characters from each other. (Hint, hint.)

Also I'm listening to the Sans Stronger Than You on loop. And... maybe the entire Undertale OST. *cough cough Megalovania cough cough*

Thanks for reading HumanUnderTale! (Also that's a really weird name but I have no idea what to call it.)

:3