Sans wakes up in a cold sweat. He chokes and then starts coughing, clawing at his neck. Sans's eyes quickly dart around the room. It's not his room. He sits up as confusion sets in. Why...... Why is he scared? Sans shakes his head, adjusting to the new memories that are making the old ones dull down. Exhaustion weighs him down. Another nightmare woke him up too early.

The bedroom is remarkably ordinary. Sans soon realizes why. He's in Undertale. It's not the original, of course, but Sans is part of a copy of the original universe for the day. Sans rolls over and burrows back into his blankets. It's too early for this. Sans feels heavy and worn out. He wouldn't mind laying in bed all day. The bedroom door slams open right as Sans is falling back asleep.

"Sans! Get up, you lazybones!"

Sans only groans response. He doesn't move. Footsteps stomp into the room, and Sans is yanked out of bed. His blankets fall away, and Sans is left staring blearily at his brother. Papyrus holds him at arm's length in the air.

"You can't lay in bed all day, brother. Your sentry station can't be empty for the entire day!" Papyrus complains.

"Oh come on, Pap, I bet it would be real rib-tickler for Undyne if we both played dead for the day," Sans replies, suppressing a chuckle.

Papyrus drops him in utter disgust. "I am sure Undyne would NOT find our absence amusing! Hurry up and come down for breakfast." With that, Papyrus storms out of the room, muttering under his breath about the annoyance of puns. Once he's gone, Sans lets out a little laugh. He's still in a heap on the floor. He was expecting that reaction, but Sans loves to tease his little brother. He remembers taking care of Papyrus as a baby bones. Right now, it feels real. Sans's dread for the coming day is all the more real because of it.

Sighing, Sans finally gets up and pulls on his favorite blue jacket. It's clean enough. Sans makes his way into the hall and down the stairs to be greeted with the banging and clattering of pans. He swallows nervously. Sans loves his brother, but Papyrus's cooking? Not so much. The kitchen smells like sulfur when he walks in.

"Hey, Pap, I think I'm gonna get to my post early. I have a good feeling about today," Sans says. He smiles as he walks in, but the second half of what he said is a lie.

"Are you sure, Sans? What about breakfast?" Papyrus asks, setting down the pan of spaghetti sauce he had been cooking.

"No worries. I buried a container of pasta in the snow next to my station."

"That is not sanitary!"

"Maybe so, but it's still your cooking. It's no impasta."

Papyrus yells and throws a tomato across the room, barely missing Sans. The elder brother laughs and ducks out of the house before any more projectiles can be thrown. Sans doesn't feel bad for skipping out on breakfast since it happens often enough in this AU. Instead of heading for his station, Sans turns towards Grillby's bar.

The restaurant is always lively no matter the time of day. Sans greets each monster as he walks through the tables. They return his easy smile and crack up at his jokes. Grillby's is one of Sans's favorite places. It's nice to have somewhere to relax where it's nice and warm. The easygoing environment helps settle Sans's nerves.

"I'll have the usual, Grillby," Sans says once he is at the bar, wearing a smirk. The fire elemental behind the counter sighs, clearly fed up with Sans's strange addiction. Nevertheless, Grillby pulls out a bottle of ketchup from under the counter. Sans thanks him before paying and heading out of the bar. He takes a sip of the ketchup and nearly gags. It tastes awful to drink it straight. Confused, Sans takes another gulp, and to his surprise, it tastes perfectly normal. It takes him a moment to realize what happened. Sans slipped out of character. For a second, he wasn't an Undertale Sans. He doesn't know if he was simply himself or someone from a different life he lived, but for a moment, he remembered distinctly hating ketchup. Sans drinks another sip. How could he dislike ketchup? It's delicious.

Sans doesn't walk back to the road. Instead, he circles around to the back of the restaurant to take a shortcut to his station. In a flash, he's standing in a little wooden shack with a stool shoved into the corner. Sans pulls out the stool and sits down to drink the rest of his ketchup. His sentry shift usually consists of staring at nothing. The human's fall is unpredictable, sometimes with weeks between them. Unfortunately, whenever Sans wakes up, the human falls hours later. Sans can feel the coming storm like a rising itch. Each minute that goes by brings it closer.

Sans knows the exact moment that he has to get up in order to see the human exit the Ruins. He steps off the road and into the trees. Sans dreads seeing the human. Once he does, he'll know if Papyrus will have to die or not. Sans is sick of watching it happen. He doesn't understand why the human plays these sick games. Is letting the monsters live in peace too much to ask? Hidden in the trees, Sans stares at the Ruin doors in dread. He waits. And waits. The human is late. This isn't how it's supposed to happen. Sans's unease grows by tenfold.

When the door finally opens, Sans flinches. It's not a human, but a monster. Sans freezes in shock. A black-boned skeleton walks out of the Ruins. There aren't supposed to be any other skeleton monsters besides Sans and his brother. The more he looks, the more baffled he becomes. Sans thought that he was the only one to know about the Multiverse. Could this monster be some sort of traveler between the AUs? This monster has almost the same facial features and body structure that Sans does, the other only being taller. The stranger has red eye sockets and bright blue tracks running from their eyes. He wears a tattered trench coat with a dark blue scarf wrapped tightly around his neck. They are covered in monster dust.

Sans is not afraid. Sometimes, he knows things that his hosts couldn't possibly know. Sans always knows what AU copy he's in despite his hosts not knowing. When he looks at this black-boned skeleton, even with the monster dust, Sans knows that he shouldn't be afraid. He walks out of the woods behind the stranger without any fear. At the noise, the other whips around with a growl and drops into a fighting stance. Sans doesn't react. The two of them stare at each other in a whirl of confusing emotions.

Sans knows this monster. He feels a strong sense of familiarity, though he has no idea if or where they've met before. As he stares, a name rises like an ember in Sans's mind. The behaviors and memories of this particular universe peel back enough for Sans to think clearly. He tips his head forward in acknowledgment, "Greetings, Balanckeeper."

The other is so surprised by the words that he jumps back out of his fighting stance, expression shifting to absolute shock. He regards Sans with a wary speculation, uncertain if he should speak or continue on with his job. "......... No oNe....... NO one has callEd me thaT in a very lOng timE," he finally says, squinting his eyes, "Who aRe you?"

The glitch voice does not surprise him. Sans opens his mouth to reply, but finds no words. Who is he? Sans doesn't have a name of his own or even his own body. He has no clue who or what he is. Sans tries to ask the stranger for his name, but they're interrupted.

"ERROR!" someone screams, angry and spiteful. Sans flinches and turns to look, but he's abruptly yanked forwards and tossed into the trees. The lines under the black-boned monster's eyes pull away at his touch. They form light blue strings, and Error uses them to grab Sans's soul and move him off the road.

Sans lands harshly and rolls into a tree. He groans, rubbing his aching skull. He can still see part of the road from his spot ten feet into the treeline. Another skeleton has appeared out of nowhere. He's the same height as Error, but with white bones. Black, swirling lines creep up his arms and neck. Is this another Multiverse traveler? He wears a light blue jacket tied around his waist over a pair of brown pants. A slightly lighter tan scarf trails down his back. A sash of the same color holds colored paint vials across their chest. The way that this monster stands and holds themselves gives Sans the same feeling of wrongness he had experienced when looking at Swap's reflection. Something isn't right. Hidden in the trees, Sans remains perfectly quiet and still so that he can listen in on the other's conversation.

"Why do you keep doing this!? Do you find this funny? You think of all these monsters as playthings! I won't let you keep killing them!" The white-boned skeleton is still screaming. He seems to think that he's in the right even after hurling those terrible insults. Sans is very confused by the situation. His own memories are foggy and unclear, but he knows for certain that Error has some critical role in the Multiverse.

Though he tries not to let it show, Error's hurt at those accusations is plainly visible. He clenches his fist and takes a moment to come up with a reply. "You'rE the oNe kilLing the MulTiveRse, Ink." Ink growls at that, his eye lights shifting to red shapes. Sans finds his level of aggression to be very strange. Error is standing in a defensive form, but he remains cool and level headed.

Ink throws himself forward and runs at Error so suddenly that Sans barely sees the two meet. Error ducks out of the way to avoid the giant paintbrush that Ink swings. What kind of weapon is that? The same strings that had tossed Sans like a rag doll reappear. Error uses them to try and tie up the other. Ink snarls at the tactic, and bright red paint gushes out of the top of his bruh and covers them both. The red paint is corrosive. It eats away at the strings and sets Ink free without harming him. Error, on the other hand, groans as the paint burns him. Some of the drops barely missed his eyes. Sans shudders at seeing that magic work. How could someone ever use it on another living being?

The fight continues to become more vicious as it goes on. However, Sans notices a strange detail. Error will prepare to summon an attack, only to falter a moment before firing a Gaster Blaster or impaling Ink on a wall of bones. This leaves the other openings to get damage in. Error keeps getting hit much more often then he should be because he's hesitating to severely injure Ink. It has no effect. Ink seems blind to this, and keeps fighting as hard as he can. The two of them seem evenly skilled in combat, but Error is only dodging the worst of the hits.

Sans can't take watching it happen. It hurts him to see other monsters be injured. Forgetting the fact that it goes against all the rules of how he should be behaving, Sans jumps out of the trees and calls on his borrowed magic. A Gaster Blaster forms at his side, and Sans doesn't hesitate to fire it. Ink never saw it coming. He was solely focused on Error, and gets blasted into a tree when the beam hits. It's the first Blaster that has touched Ink for the whole battle.

Error looks up and stares in astonishment at Sans. No one has ever defended him before, or at least, not in any living memory besides his own. Ink looks just as surprised, but not in a good way. He can't believe that some random sans would attack him, the Creator of AUs.

Before any of them can say anything, the AU shudders. Sans wobbles and loses his balance, but the other two more powerful monsters remain standing. Black, glitching squares begin to leak out around the door to the Ruins until the entire door glitches out of existence.

"You already started!?" Ink screams, almost shaking in rage.

After dusting the monsters in the Ruins, Error made a big enough tear in the Undertale copy's code so that he AU would slowly disintegrate behind him. He can usually take out all the monsters before the AU falls into the void. It's much more merciful to kill others than let the void have them.

The AU is disappearing at a rapid rate. Chunks of the sky and ground fall away, leaving only black void behind. Ink jumps away when the earth near him starts to crumble. He rips open a swirling portal and abandons the AU to its fate. Error opens a portal as well, but hesitates and looks back at Sans. The weaker monster's eyes are huge as he watches his world far apart. Sans meets Error's gaze, understanding in an instant that there's no escape. Error disappears through his portal.

Sans yells out and struggles to his feet. The void lurches closer and closer until the ground beneath his feet falls away. The blackness seems to yank on his foot, and Sans screams as he's dragged into the darkness.