Hey Everyone!

Interference in bold, puns and memories in italics, magic is underlined.

-text- indicates either texts, or mental "talking".

All Undertale stuff owned by Toby Fox, else me, or a reference.

The grinning skeleton steals your pie. You are not okay with this.

Papyrus

THE GREAT PAPYRUS PATIENTLY BLOCKED THE DOOR. SANS SOMETIMES DID THIS, BREATHING HARD AND RUNNING AWAY AFTER A SIMPLE QUESTION. IF HIS BROTHER HAD NOT ASSURED HIM OTHERWISE, HE WOULD HAVE THOUGHT THEY WERE PANIC ATTACKS. USUALLY, SANS WOULD BE FINE AFTER HE HAD HAD SOME TIME ALONE AND PAPYRUS DID NOT ASK THE QUESTION AGAIN. THIS TIME, HOWEVER, HE WOULD NOT BUDGE. HE NEEDED TO KNOW IF GASTER WAS IN TROUBLE! AFTER ALL, HE COULD NOT REMEMBER SEEING HIM SINCE...WELL, A LONG TIME!

"Sans, please do not run from us. We only wish to know what has happened to Gaster," THE QUEEN KNEW HIS BROTHER? WOWIE, THAT WAS EXCITING! SHE SEEMED TO KNOW EVERYONE!

HIS BROTHER WAS FINALLY CALMING DOWN. HE SEEMED TIRED AS HE WALKED BACK OVER TO THE COUCH, GESTURING FOR THE GREAT PAPYRUS TO SIT DOWN NEXT TO THE QUEEN, "well, better get comfy, 'cause it's a long story."

Sans (a few weeks after the first boysenberry pie)

Sans was worried. The Scientist was keeping them later and later. Papyrus hadn't had a bedtime story for ten days, and Gaster was acting...strange. After he'd been forced to stop halfway through a change three days ago, his skull had never completely reformed. He almost seemed to have lips now - they even moved. They'd tried it on Sans the next day, and his jaw had fused to his skull. It hadn't really stopped him from talking, and head just broken down food with his magic, but...he missed being able to REALLY smile.

Gaster had gotten angry when he saw that. He'd gone after one of the assistants with hisbone attacks...somehow, his hands had ended up under the drills. An 'accident', just like Sans' eye. He'd figured out how to float a small spell in the useless socket so that it looked like he could see. He'd been practicing different expressions, but sometimes he just couldn't be bothered to try. Why should he care about looking normal when his life was one giant horror movie?

Yesterday, the Scientist been jumping up and down, twirling his assistants 'round the lab. Seems his OTHER project had been completed, starting up without a hitch. Half the Underground was already hooked up to the power, and they planned to add Waterfall and Snowdin over the next few weeks. The King himself had stopped by for the startup, and approved unlimited funding for the lab - something the Scientist had been hoping for, since it meant he could put more gold into the other projects Asgore knew nothing about. Hooray.

His joy hadn't stopped him from working on them, though. Sans couldn't remember the trip home, only the pain. They'd been trying out this thing called DETERMINATION, and it hurt like hell. He'd felt like the only thing keeping him from melting under the pressure was his magic, always so powerful. Then they'd forced him change. That...hadn't worked out so well. On the plus side, Papyrus now had these cute little skulls to play with, provided Sans could work up the energy to pull them out of...whatever that place was called.

Gaster hadn't fared much better, but at least he hadn't been forced to change. They'd made him summon his bone attacks...they'd been different. Instead of the usual femurs, he'd wound up with a dozen floating hand. He'd waved them around a bit, then one of the assistants had opened the test chamber to tell him to stop. Sans had seen the hands fly over and grab the assistant's throat. They'd come away with only 2hp.

This morning, he'd woken up to the sounds of cooking in the kitchen. Pap, probably. Gaster wasn't up for cooking much, nowadays. He sat up, feeling the heat of the DETERMINATION roiling through him. Guess that wasn't going away anytime soon. He threw up.

When he'd finally run out of gook - and how did he manage to throw up through a closed mouth, anyway? - he'd washed off his face as best he could, and tossed up the eye spell. He couldn't seem to manage more than a pinprick today. Maybe Gaster would-

"Children, you are late, and I am very tired of waiting for you. Come out!" No, no no no No NO! PAPYRUS WAS DOWN THERE! He ran out the door of his room, vaulting the railing and dropping to the floor. Ow. He was still get used to the whole 'no depth perception' thing. When he managed to pick himself off the floor, he saw the Scientist holding Papyrus by the strap of his favorite apron, the one with the cute little fire and the words, 'Here's a curse for you: May all your bacon burn'. The Scientist was grinning a grin that terrified Sans to his SOUL.

Sans heard Gaster's door slam above him, and felt the beginnings of a plan form. If he could just get the Scientist to put Papyrus down… "I did not realise you wished us to arrive before sunrise this morning, sir," Sans could feel the icy stare of his brother even though it wasn't aimed at him. Gaster could make anyone feel their sins crawling up their back. Sans dreamt of one say developing a stare like that of his own.

"Well, for once, I'm glad you did," the scientist was much too cheery in the morning, "You've been holding out on me. I was under the impression your younger brother had died with your mother, and now this!" Papyrus turned a confused look on him, but Sans was as confused as he was. He'd thought the Scientist just didn't want to bother with another test subject. Did Gaster tell him the lie to protect Papyrus? "Get him cleaned up, we're already late."

He dropped Papyrus, kicking him over to Sans, who growled at the cruelty. He scrambled over to his brother, wrapping him in a hug and putting his own back between the Scientist and his brother, and turned his skull, looking for Gaster. The moment their eyes met, he knew Gaster knew what he'd planned. He let the memory of a grin spread across his face, and teleported.

The heat of Hotland felt like a solid wall, stirring up the DETERMINATION in his SOUL. Papyrus struggled in the hug, but Sans needed to know they'd arrived safely. He looked up...at the bridge to the CORE. He scowled. This wasn't where he'd been aiming. He'd wanted to reach the Guard Station, not the Apartment Complex. He was surrounded by the very people he'd hoped to avoid - most of the monsters who lived in this building worked for the Scientist.

Well, it'd have to do. He vaguely recalled hearing that they'd installed an elevator to the Capitol inside the CORE, and from what Dad had said, their king was a pretty good guy. He'd said something about going to New Home if they ever got seperated...King Asgore would help them, surely. He just had to make it there.

He didn't make it. Halfway through the maze of corridors, Sans tripped on a loose wire and bashed his head on the wall. The world spun around him, and suddenly he was on the ground, insistent gloves tugging at his shirt, "SANS! WAKE UP!" He managed to turn his head, and saw the fight.

Not twenty feet away, Gaster was limping towards them, his summoned hands tearing at the walls and throwing anything they could at the figure behind him. It was the Scientist, clearly furious and desperately trying to protect the machinery around them. Sans felt numb. The monster cared more for his precious CORE than for the lives of three children.

The Scientist ducked under a flying girder, coming up fighting. His cogwheel bullets flying past Gaster, taking out hands right and left. Sans threw up a bone shield and felt it crack. He'd never been any good at solid attacks. Another round, the crack spread. Two bones near the center collapsed into dust - he was exhausted. He was fighting the DETERMINATION, the heat of Hotland, the dull pain of all his injuries, and the long-time lack of sleep; fighting, and losing.

Sans felt his shield shatter, curling himself around Papyrus, waiting for the pain...it didn't come. Fearfully, he turned his skull. Gaster had grabbed the bullets and fragments of bone, hundreds of hands wrapping around the debris - too many. Sans saw the exhaustion in his brother's body as he turned face to the Scientist. Sans saw his expression, too. Resignation.

The Scientist grinned wider, fist rocketing forward to knock Gaster to the ground. Gaster reached out, his own hand grabbing the arm. The Scientist struggled, but Gaster wouldn't let go. Another fist arced down, only to be caught by a skeletal hand. He tugged back, but could not free himself from Gaster's grip. He looked up, furious - and stopped dead, mouth open wide.

Sans couldn't hear whatever Gaster said next. He couldn't tell if it was an insult, an apology, a judgement, a plea. He only saw his brother throw himself and the Scientist off the walkway into the CORE. Sans screamed...but nobody came.

Toriel (present)

I...do not know how to react. The story Sans told was so horrible...how can it possibly have happened? And yet...and yet...I can tell he has not told us everything. I do not believe the outline of events was in error...he has left out details, though. Why would he...Papyrus. Sans is so protective of his brother - if there is anything in this story that he believes would hurt his brother, or affect his cheerful innocence, Sans would omit it without hesitation.

The way he is looking at me, he must realise I know he has not told me everything. If what I suspect is true, I do not wish to push him to tell me while Papyrus is near. I pull out my phone and text him.

-Sans, you will explain to me what you have left out later, will you not?-

He starts, then pulls out his phone. His eye lights dash back and forth, then he looks up at me and nods. Good, he is not unwilling to trust me, even after...that. How could Asgore have let something like that happen? That is...Sans mentioned the completion of the CORE as a major event in the Scientist's life, that it allowed him to pursue his other research without worrying about funds...he did not know of this, did he? Even with the horrible things he allowed to be done to the fallen children, he would not have accepted this.

"GASTER...FELL INTO THE CORE?" Papyrus' voice shook. He did not remember his brother's death before this moment...why is Sans doing this? Why did Sans ask me to bake him the boysenberry pie, and ask his brother to rearrange their house? He has spent a very long time protecting his brother from this memory, has he not? How could he not have realised this change would allow him to remember?

"Sans...why have you asked us to do these things? You wished to help someone else remember Gaster, did you not? Who did you wish to aid?" Sans winces.

"i...asriel's told you about his SOUL reincarnation theory, right?" That...is not what I expected him to say.

"Of course. He believes that, as the SOULs of Boss Monsters, and those monsters whose impact on history is greatest, linger after death for a short time, it is possible that they might be capable of some kind of afterlife. He believes that they would not be powerful enough to reach another plane of existence without aid, but perhaps they might be able to linger here long enough to find another life to live."

He nods, and Papyrus' eye sockets light up, "YOU BELIEVE OUR BROTHER HAS REINCARNATED, AND THAT YOU KNOW WHO HE HAS REINCARNATED AS! BROTHER, THAT IS-"

"i'm not sure. i think it might be him, but...he didn't exactly die," My brows furrow. The only time I have heard of that a monster has not completely died is when Doctor Alphys was experimenting with DETERMINATION, and as Sans has never mentioned any relation to one of the Amalgamates, I do not believe that is what he means, "the CORE is...strange. it converts geothermal energy from hotland's magma to magical electricity, right? well, it does that by passing it through a ring of something called the void, which bends reality to its breaking point. the void is...dangerous. we don't know much about it, except that time doesn't seem to affect it. at all. literally no time occurs inside the void, or maybe the void has an entirely separate timeline all its own. anything which passes through the void...changes."

"gaster fell into the center of the CORE, where that ring of void is. i saw him...he didn't die, exactly. he...separated? broke apart? something like that...think of it like that old song...mind, body, and SOUL. one piece was sucked into the void - his mind. one piece fell into the magma - his body. the last piece...scattered across our timeline."

"What do you mean by that?" My arms are folded, and I see him shrink a little, but that sounded far too much like an evasion.

"times weird stuff, trust me on this. loops, breaks - holes everywhere. sometimes it's hard to understand why it doesn't just fold in on itself under the strain. human physicists have this theory they call the multiverse, where every decision creates two or more alternate realities - one for every possible outcome. the truth's stranger than that."

"not every decision creates a branch point...most don't really have much of an effect. some, though...some are pretty powerful. points so impactful, reality breaks around them, old branches that have been parallel for ages get pulled into the meld...weird stuff. most things exist inside the timelines, so they just get brought along for the ride...separate realities which have no inkling of their other selves."

Papyrus shifted from foot to foot, clearly uncomfortable with where this conversation had ended up...or perhaps he was aware of where it was going? "some people, though...some people don't exist entirely inside a timeline. bits and pieces hanging outside the ride, ready to be caught up in any passing car...something like that, anyway. the more of them that is outside the timeline, the more the branch points affect them. sometimes it's as simple as deja vu, or dreams...sometimes more."

"our timeline has been pretty badly messed up - warped, twisted, cut and pasted, over and over and over. hardly any part of it that isn't compromised," I open my mouth to ask how he can possibly know this, how it happened, but he raises a skeletal hand, "trust me, lady, you don't want to know. it's not a pretty story."

Papyrus reaches over to his brother, and I notice that Sans is shaking. I decide that this is one omission that I do not want to understand. Papyrus lays a gloved hand on Sans' shoulder, and he stiffens, then grabs the hand and holds it tightly. It is as though touching his brother, knowing Papyrus is truly there beside him, is the most important thing in his universe, "...anyway, gaster was pretty far out of the timeline when he...fell...into the CORE. the death of the royal scientist would have to be a pretty big change, wouldn't it?"

"the bits of gaster that existed outside the timeline made it impossible for him to reform in it. the bits on the inside became a paradox...something which cannot possibly exist in the normal course of reality, but they did. time isn't so good at dealing with paradoxes, it likes to spread them out, so that any given moment has as small a concentration of paradox interference as possible - principles pretty similar to entropy."

"so, the bits of gaster that existed inside the timeline were pushed apart. a SOUL can't take that kind of strain though, can it? so it broke. but since his mind still existed...since part of his SOUL remained outside of time...it couldn't fade away. so he died, but not exactly. half-died, half-lived. didn't help that his body turned to dust in the magma - his magic released to mix with the bits of his SOUL that existed inside the timeline."

"so, whatever was left was similar enough to a shattered SOUL to reincarnate, but...there's still that part outside of time. i've been trying to track it down for years, but i think it ended up in the void...that's the only place my readings would come out looking the way they do. i've worked out that there are places inside the void that correspond to places inside our timeline...alphys has helped me pinpoint a few, little grey rooms that appear occasionally in waterfall and at frisk's college...we know that the SOUL is drawn towards its body...if i could get the reincarnated body of our brother, aware of its identity, into one of those rooms? i think the rest of gaster might be drawn out of the void."

We sat in silence while the clock ticked beside us. Finally, a thought struggled out of the buzzing depths of my mind - what makes a SOUL? "Sans...if this works...if your theory is correct...the SOUL of whoever this...half-reincarnation...is, it would be lost, would it not?"

The idea seemed to trouble him, "i...i don't know. it would depend on a number of things...how much of his SOUL is in there, for one...the relative strength of their magics...their intentions…" He sat in silence for a long time, squeezing Papyrus' arm every so often, "i don't know. maybe alphys could find an answer…?" His voice drifted off, his eyes closed - how do they do that? After some time, they opened again, "i don't think i could do it, if it meant overwriting someone else's SOUL…"

I reached out, troubled at the torment I could hear in his voice, "Then we will hope that that will not be the case, will we not?'