In the late morning, when the sun had been up for a few hours, there came a knock on the door that neither of them were expecting; rubbing her tired eyes and munching on what was left of her cereal bar, Frisk called out to Toriel that she would answer it.
But when she made it to the door, her hand stopped a few inches from the knob. She bit her lip, thinking of last night, and tried to check in the peephole. Unfortunately, it was too high for her. The child jumped up and down several times trying to align her eye with the little glass window, but couldn't see anything even when she thought she could see into it.
"Frisk, are you going to get the door?"
There was another knock; Frisk' back felt tight as she called back, "Yeah, just a second!"
When she turned the knob, someone pushed the door in lightly from the other side; Frisk gulped and stepped back to avoid getting nudged. When that was out of the way, her eyes proved right that sense of foreboding in her gut and the blood drained out of her face. Standing on Toriel's doorstep was Red Sans, wearing a big grin and sweating.
At the very least, his eyes also widened with surprise. "dude, it's like 10:00am. the hell are you doing at home?"
"Oh... school... got cancelled," she said, hand latching onto the door and gripping it hard. He was wearing a fluffy blue coat that looked too warm for summer; maybe that was why he was sweating today. "Too many kids called in sick."
"that's a shame," Red Sans murmured back, glancing around Frisk's shoulder. Then his gaze turned to the kid proper and he laughed, "what's with that face, twerp? wanna hear a joke?"
"No-"
Giving a huge grin, Red Sans took a quick look over her shoulder again and then went on, "what did the blind, deaf, mute quadraplegic boy get for his birthday?"
Frisk bit the inside of her cheek. "What did he get?"
In a voice tense with anticipation, Red Sans said, "cancer." The look on her face must have told him immediately what she thought of the punchline, because it was followed up by his howling laughter. "ahahahahahahahahaha it's just a joke, come on!"
"Darling, who is at the door?"
Red Sans remained silent, and sweaty, while the child turned back in the direction of Toriel's voice. Gulping and taking a deep breath, she called back, "It's... ... Sans, Tori."
"Oh! Let him in, then."
Frisk didn't budge, though, continuing to stare at him with a pale face. Red Sans looked back coolly, not making a move to push, drag, or strike her like he did some hours ago. So, slowly, without saying any words, she stepped back to let him inside. She closed the door behind him and yawned hard.
"she's alright with you having friends over?" The terrible monster asked, the tone mocking to her suspicious ears.
But she just nodded weakly. "Not grounded... after last night."
Grin turning sheepish, Red Sans rubbed his skull. "yeah?" He raised his voice and called into the living room, "how's it goin', tori?"
"Oh, it is going well." Came a call back. "I am just catching up on grading papers, now that I am free for the day."
Red Sans looked to Frisk expectantly. "grading papers?"
"... She's the teacher," the child uttered, and Red Sans barked a laugh. Frowning, she spoke in a lower voice that Toriel hopefully couldn't hear in the slightest, "What do you think you're doing here?"
As if last night had never happened, he shrugged back at her. "hey relax, pipsqueak. i'm not here to hurt ya."
But she refused to be fooled. "Then what are you here for?" She hissed. Her eyes then widened, "What did you do to Papyrus!?"
"he's dead, obviously," he said, and Frisk's throat closed up. Red Sans began laughing even harder than before when she choked vowels aloud, "AHAHAHAHAHAHoh my god kid calm down he's fineahahahaha-"
"Now what is so funny?" Toriel called to them both.
No; if she said it was a normal, or even bad joke, then her adoptive mother would come over to hear it for sure. Frisk screwed her eyes shut and, flashing them open, directed her hardest glare at Red Sans- Red Sans still stifling laughter. "Nothing, Mom!"
The huge grin was still on his face, but finally Red Sans seemed interested in speaking seriously, after looking around Frisk's shoulder again. "okay listen," he cleared his throat, face returning to his normal menacing smile, and she stiffened. "i actually was wondering, if you've got nothing else to do, uh... is it too late for that date thing you asked me on?"
"...What?" Some of her suspicion, and some of her tiredness too, while she was at it, ducked below the surface of her surprise.
"what you mean 'what'?"
Frisk quickly shook her head, "I mean- what?" Was this just a trick to get her into a secluded location? "Why are you agreeing to this all of a sudden?"
He rolled his shoulders, shooting another glance towards the living room- she followed it, wondering if Toriel was coming to greet them, but didn't see anything noteworthy. "don't you remember? i already agreed to it. literally a couple hours ago."
"But that was before Papyrus found out-"
"yeah, yeah, i know, i got a little peeved." He waved his hand at her dismissively, and the child's nostrils flared. "big deal. i'm not mad anymore. so, uh, lemme make that up to you, okay?"
Frisk still glared at him; at the same time, he sounded genuine enough- considering it was him. Not to mention that he was getting all sweaty again. And she had a lot to gain from going up there.
So the child half turned and yelled, "Mom! Sans wants to take me to Mt. Ebott today!"
Red Sans smiled at her with huff of relief, pulling a bottle of spicy mustard out of his coat pocket and drinking it, somehow, through his teeth. With his white normal eyes, the smile almost looked friendly to Frisk. Meanwhile from the living room, there was the scrape of paper against paper while Toriel stood up. "Mt. Ebott? That is a long trip, is he prepared for it?"
"don't worry tori, i brought lots of food-" Red Sans insisted, when Toriel appeared in the doorway to regard them both with warm eyes. He choked a little on the mustard and cleared his throat, "uh, uh, wouldn't do to let a kid starve, y'know?"
"Indeed." Her adoptive mother, in a newly laundered set of robes, leaned against the doorway into the living room and slowly studied Red Sans. "I like your new coat, by the way."
"uh. thanks."
The way that he looked at Toriel made Frisk want to be physically ill, or so she thought while she was wringing the hem of her sweater and trying to keep a disgusted grimace off her face. "Yeah mom we'll be just fine," she said, trying not to speak through gritted teeth. "And I know you're busy and all, so can we just go?"
"Oh, you are in such a hurry," she laughed, ruffling the child's hair. "I suppose if it is so far away... it would be good to get a head start. Please promise me you will keep them from harm, Sans."
Luckily she didn't notice Frisk staring daggers at Sans as he said, "... uh, yeah, i, uh, i promise."
Soon the door creaked shut behind the two of them, the sun shining brightly that morning. Frisk looked back at the building and then shook her head, stepping after Red Sans. "She's always acting so weird."
"she's stressed out," he said back, squeezing more mustard into his mouth. The condiment didn't seem to impede his speech at all. "give her a break, brat."
If he could just stop calling her a brat, that would be great. Frisk held her hands behind her back. "If you say so."
"as a matter of fact, i do," he grunted, putting the mustard away. "majority of your class gets sick, that's cause for concern. i bet you haven't asked her once how she's feeling."
It would also be stressful to find out one of your friends was replaced by his evil twin and is probably dead by now but you told me not to talk about that. The child rolled her eyes and said in a sullen voice, "My Sans doesn't lecture me. And you haven't asked her either."
"maybe i will later." He stopped, taking a look around, and Frisk did the same. No other monsters sprang immediately to their vision. "well, if you still want to do this, whaddya say we take a shortcut to our destination?" He held out on clawed hand to the child.
She accepted it, albeit with knotted nerves. "It's better than a bus ride, I guess."
The moment she took his hand, Red Sans' eye flashed and the world distorted around them. Air fled to fill the space their bodies left behind, as they disappeared from New New Home altogether. Instead, they shoved air aside as they immediately took up space in the entrance cavern within Mt. Ebott, Frisk falling to her knees and letting waves of dizziness roll off her from the jarring transition. It was how she expected to feel when her particles were picked up and placed somewhere else with no journeying in-between.
While she resisted retching, Red Sans beside her chuckled. "get a stronger stomach, twerp."
She did her best to ignore him, getting used to his teasing by now. Picking herself off the ground, Frisk took in their dark surroundings as her eyes adjusted. The same cave with the unintelligible words etched onto the walls, the floor littered with ever more scraps of underbrush blown in by the mountain wind. There was a whistling from somewhere while it blew through the holes in the ceiling, taking her back a long time for a second. "...Oh, this place again?"
Red Sans shrugged. "it's the only place i know on this mountain. it'd be irresponsible to shoot for anything else."
"You're supposed to take someone somewhere special when you're on a date," the child remarked, crossing her arms. "How about I show you where that is?"
Red Sans didn't answer at first, grinning, but when Frisk turned and experimentally walked to the exit he followed after her. "what, did you also take that dating rulebook out of the library?"
"I just have a good memory. I've dated before." She resisted asking him why he had done that too.
The outside was indeed windy today, and she was grateful for her sweater as always. The grassy slopes of Mt. Ebott changed color every minute as the wind took the blades and flowers in every other direction, summer pollen drifting through the air. It was always loveliest on the top, when blossoming nature could be seen for miles around. And on the very top, where it sometimes got cold enough to snow- especially since the cold-climate monsters had moved there- was also located the town of Snowdout.
It wasn't Snowdout, and it wasn't the top of the mountain, that Frisk was hiking to, however. It was, however, farther up than around the base of Mt. Ebott where the cave was located. Her aim was the ledge where she had first come out of the Underground, which was on the other end of the mountain, on the second hill sprouting from the base, and it obviously quite a climb. It had taken her a long time to get to that point from the cavern when she was actually in the Underground, although granted there were a lot more obstacles in her way. Were she not held back by anything, it would have taken only a couple hours. And presumably she wouldn't take hours to get to the ledge on the outside.
Although it wasn't long before she heard Red Sans huffing and had to stop, the monster sweating and breathing funny. "why does it have to be so far?"
"It might go easier if you weren't wearing that heavy coat," she called, walking back to where he had lagged behind.
"screw you," Red Sans said with a manic smile, "this coat is my something nice."
She blinked, "Your what?"
"yeah," he pulled out a familiar little book that had Dating 101 printed on the front, flipping through the pages. "step three: put on nice clothes to show you care. and i'm sure you know, new clothes are nice clothes. hence," he slammed the book shut and exhaled sharply, stashing it away in his pocket, "this new coat is my nice clothes."
"Oh!"
The mistake she made in this situation had suddenly become apparent to her. Hurriedly, Frisk took off her locket.
You equip the faded ribbon.
"Now I'm wearing nice clothes too."
"hah," was all he said, lazily winking in her direction. "you look like a dork."
Something did occur to her, though, while she stuck her tongue out at the skeleton monster. "... But you didn't know that I was ungrounded until I told you, and you already had the nice clothes on. So how did you know...?"
Red Sans' smile became a little frozen. "huh? ...you wanna know why i was already wearing dating clothes?"
Frisk nodded.
"uh... how about you take me to this place instead of asking dumb questions?"
On the ledge of Mt. Ebott, everything this side of the mountain was plain to see. The dense, lush forests that covered almost every space in sight, the fields of yellow flowers that peppered even the few meager free spaces, and the village that lay a short walk from the base of the mountain (taken over by the froggits.) Farther out one could see a coastline in the far distance, the water lit up by the rising sun. On either side of the coastline, a second mountain and the skyscrapered human city that Frisk once came from. Everything was washed in a blue morning hue, and in the evening it would turn gold with the setting sun.
The climb up didn't bother her if only because of the sights themselves. Next to that human city was a rather new sight of New New Home, rising bit by bit each day. The progress that the monsters had made to relocate their capital, all in in just about a month, was amazing.
Red Sans had stopped complaining at some point and just stood next to the child, catching his breath.
"hahh... hahh..." He looked over the whole landscape and then closed his eyes. "imagine stargazing from here."
"I like it too." Frisk sat down, swinging her legs over the edge, and just enjoyed the wind cooling the sweat from her face. Not far behind them was the entrance into Asgore's castle, one of her easier places to reach SAVE points. Still, for now the child didn't mind staying where she was. She hadn't died once over the past several days, and it didn't feel like she was going to right now either.
Nothing interrupted the stillness on the mountain, not even Red Sans making another horrible joke. Instead, he was also overlooking everything without moving a muscle. "i'm jealous," he said finally, quietly, like it was to himself. "nowhere in my world is there a view this nice."
The difference in how he was acting today was remarkable, when only last night she had seen a terrifying side of this Sans that yet lingered in her mind. She yawned and turned her head and gaze in his direction, until his eyes flickered to look at hers. Cautiously, Frisk ventured, "You keep saying stuff like that. 'In your world' this, 'this version' of that. What does it mean?"
"i have a feeling if i tell you, you won't keep it a secret," he snapped.
She clasped her hands together, eyes wide. "Pleeeeaasse?" Red Sans heaved an aggravated sigh, and she could only hope that the good mood he was in would be enough for her to get a proper answer. "Please... ?" This Sans, she had noticed, talked a lot more than her own.
Sure enough, he rolled his shoulders again and uttered, "eh. why not. kind of told papyrus already, anyway." The brow ridge of his skull raised as he surveyed her eager face. "i don't think that you'll understand all of it, though."
"That's okay," Frisk said, easing around and sitting crosslegged in front of him.
He snorted, easing tension from his stance. "okay kiddo, pay attention because i'm gonna give you a little quantum mechanics lesson."
You buckle in for a lot of words that make no sense.
He cleared his throat once, and then, twice, glancing down at his feet and back. "the basic measurement of the quantum state of a system, so far as quantum mechanics is concerned, is the wavefunction. uh," he scratched his head, grinning sheepishly, "i only saw that explained in one textbook before, but supposedly the one who posited that was some human named werner heisenberg in 1927. it's basically that you can take any portion of the universe, big or small, to put under analysis. The wavefunction is kind of a description of that portion being analyzed, a description of every possible eigenst-
"...to put it in simpler terms," he restarted after a moment, catching Frisk's already glassy eyes, "let's use you and me on this ledge together."
Frisk stood, brushing dirt off her pants. "Okay. We're on a ledge."
"there are many, many ways that this kind of encounter can go," he gestured to their surroundings. "for instance, i could walk right up to you and push you over the ledge. or i could throw a stone at you. i could also decide to use a magic attack on you, all various ways of bumping you off once and for all."
"...um..." Frisk reached a hand into her hair, preparing to unequip the faded ribbon and put on the much stronger locket again.
"but," he went on, as though oblivious, "it's equally true that i could do nothing at all, or that something else could take you out. these are all possibilities of this single measured moment, and there are countless more. you don't know which one will occur, so technically they're all possible. the superimposition, the collective of all these possibilities at once, that's a little like the wavefunction."
There was a pause, then, while Red Sans opened his eyes again and studied Frisk. "uh, are you with me so far?"
"I could die a whole lot of ways right now," Frisk repeated as she sidestepped away from him.
He snickered, "yes but to be fair, i could die in a lot of ways too. we'd, uh, we'd be here all day if we listed every single possibility. but the wavefunction lists every single one, in a way. human scientists determined that this was only true of a quantum state that was being unobserved. they say that once observed that wave function collapses, and then only one possibility remains of the multiple that we just discussed. like you not dying, that becomes the only possibility since, uh, it's the one we observe happening right now.
"see?" More breathless laughter at the bewildered, vaguely frightened expression on the girl's face. "therefore you're just fine."
"...Right."
"but that's complete bullshit," he hissed, and Frisk stiffened.
The fur lining the hood of his coat seem to fluff out as he spoke, Red Sans' toothy smile wide and white pupils big in his sockets with his excitement. "that's what this human proposed, this guy named hugh everett. the wave function collapse is bullshit. you are dead. right now, you just died."
"I don't feel like I died" Frisk whispered, taking another step back. Her heart was pounding.
"not here you didn't. y'see, everett proposes that instead of the wavefunction collapsing on observation, all possibilities in a quantum state become actualities, all at once. but in doing so, each possibility splits into another reality. each possibility is resolved by the universe splitting apart into a parallel world.
"so to go back to our example," he took out the bottle of mustard and drank as he spoke, and Frisk trembled with a nervous smile on her face. "right here and now i made a decision. a decision not to kill ya. but i could have decided to kill you a second earlier. in making that decision, the universe split. there must exist a world where i did make that decision to kill you. it's the same for you. every decision you make, every move that this world makes, splits the universe off into worlds where something different happened in its place, hell, so many worlds you can't even care about any of 'em unless you're in one.
"...something like that." Red Sans swallowed, seeming to calm down some, and looked earnestly at the child. "uh, did i lose you, kid? i tend to ramble if nobody stops me. to be honest, this is the longest i've talked about this stuff without the boss telling me to shut up."
Honestly, her head hurt, and it took a moment to realize that he didn't mean he was going to kill her. Decisions create different worlds. Somehow? Frisk rubbed her temple to combat the ache. Slowly, she said, "So you mean, you... come from... a similar world where someone made... a different decision than in here?"
"heheheh, you're pretty smart." She smiled at him, and yet he shook his head. "it's more like, in my world, multiple different decisions were made. y'see if it was just one decision, i'd be a lot more like your sans. but as it is, my world is pretty far removed from yours."
Like cousins who are twice removed? Not that she knew that phrase either. But she did miss the normal Sans. Frisk sat back down, rubbing her forearms. "So what's it like over there, in your world?"
"... of course if you prescribe to the theory of the butterfly effect, and taking into account this is the only world my machine picked up on..."
"Red Sans!"
His eyes flickered again. "uh? fuck, you called me that before didn't you?"
Face turning red herself, Frisk covered her mouth in the collar of her sweater. "I asked what it was like in your world."
The eager expression Red Sans was wearing faded, and he shrugged gruffly. "what do you think it's like? kid, look at the differences between me and your sans. then put those differences on everything else in this place, and you'll get what mine is like."
"No wonder you left," she mused into her collar.
"now you're catching on."
She didn't know where to look after hearing that. But the first thing that she thought of was her own Sans; if this one came from another world altogether, did that mean that he put his parallel world self in this place? Meaning that Sans was trapped in a horrible world as they spoke. Sans with his 1 HP and 1 DF. She was very glad that she already had Alphys on her side; this would be useful information for her, right? The child stood up. "But, um, even if it's different, there are a lot of things in your world that are like this one, right?"
"i guess." He'd spilled a drop of mustard on the coat and was distractedly trying to scratch it off, bottle set by his feet.
Frisk glanced towards the former site of the Barrier, the entrance into the underground and Asgore's castle. She had to get into there. But she was also curious, if he came from a completely separate world, and now looked over at him with as neutral an expression as she could manage. "Is there another Frisk there too, where you came from?"
Red Sans stopped moving, not looking at her. He finally said, "...they're... a thing, yeah."
"Are you guys friends too?"
His pupils flickered, growing faint, and she wondered if they would blink out entirely. "friends? ...something like that."
She grasped her hands behind her back again, innocently staring at him. "Then how come you left them behind?"
The flashing red eye appeared abruptly, moving in her direction, but he didn't budge. Frisk's breath caught in her lungs; his good mood from earlier looked to have evaporated, and she wondered what exactly was the deal with her other self. She couldn't be that bad, could she?
But then a moment passed, and he smiled big with his sharp teeth. "haha. cuz i'm a bad friend."
"-And what does that mean for me?" The child felt a chill and her arms rose with goosebumps, frowning hard.
"relax twerp, you two are... completely different. and i can adapt to a less- as you keep saying- pointy reality, if i have to." He dug into his pocket and brought out a hot cat, smothered with mustard. "for instance, how about an early lunch on me?"
There was no telling what kind of trick this was. Red Sans looked genuine but he did just admit to being a bad friend. Heck, even her Sans wasn't above hot sauce on a hot dog. Frisk took a deep breath, "Actually, you mind if I, uh, excuse myself for a minute?" Her eyes went to the entrance of the underground, and so did his. "I need to, uh, go to the bathroom."
"... like i told you before, I'm not an idiot, pipsqueak," said the monster in response. "why would you even need to take a bath right now?"
"What? No, it's so that I can-" Face flushing, she abruptly gave up and just said, "I mean you're welcome to follow me but I'm sure you don't want to."
The grimace that he was giving her looked particularly puzzled, but then the white pupils in his eyes lit with understanding. "oh, i get it. you wanna SAVE, right?" Her breath caught, and he chuckled, "my frisk was, uh, they were also touchy about that for some reason. s'okay, i don't care. in fact, i got my own little theory about SAVE-ing."
He smiled menacingly. "wanna hear it?"
Taking the hot cat he offered, Frisk nodded.
Author's Note: Ohhhh boy serious disclaimer, I am not a quantum physicist, I have not studied physics at all since highschool, and I learned about the Many Worlds Theory in a history class technically. Most of my information and terminology I took off the web. Hopefully I did not butcher any of these concepts too badly. If so, my excuse is that Red Sans only understands the theory insofar as he read about it in discarded human trash and proved a multiverse at least exists using his machine.
Next Chapter: Theorizing to the Tune of Metal Crusher
