"If a human ever comes through this door... Could you please, please promise something? Watch over them, and protect them, will you not?"
Sans' footsteps crunch against the snow as he walks toward the human child standing on the bridge. They're standing still up until he reaches them, even if he's not even using his magic on them.
"Human."
He adopts a creepy tone to startle the human. However, without having time to finish what he is about to say, the human already turns around to face him.
He easily rolls with it, extending out his left arm for a handshake. They shake his hand with their own, and in the process trigger the embarrassing sound from the whoopee cushion on Sans' palm.
The human chuckles dryly, either nervous or nettled.
"heh, the old whoopee cushion in the hand trick..."
Even if the human fell for it, something about their reaction has Sans feeling off. He pulls his hand back and returns it into his pocket.
"wait a sec... have you heard it before or something? you dont look that surprised..."
"I'm going to tell you the truth."
Sans is caught off guard this time.
It's a strange sentence to leave the human. They're addressing him like they already know Sans, completely familiar and unafraid. Especially for a human, it's strange. But as soon as it's said, Sans does know one thing. This isn't the human's first time in the underground.
"...are you usually this forward?"
Sans doesn't even alter his tone. He knows first hand time travel is a thing. He knows it's possible for there to be someone who's already lived through all the events he himself has yet no knowledge of.
He doesn't know if this human child is a friend or an enemy, but he has no choice but to address them like he would in the present. Unlike them, the present is all he has.
"Usually I barely get a word in. But I want there to be at least one time where I tell you the truth."
Sans realizes what they're saying is something self-indulgent. He realizes it's something "off-script," something that would provoke an unusual answer from him. He briefly wonders if he usually says all the same things when this human, still supposedly, goes back in time. He must, right?
He would probably respond differently if he didn't see Papyrus' red scarf flash in the distance. He doesn't know how much this child knows about him, but Sans is secretive by nature. He doesn't do things in the open.
Since he's unaware of what the child knows, he says what comes naturally to him.
"...im supposed be on watch for humans right now. but... y'know... i dont really care about capturing anybody."
The human looks disappointed, but Sans carries on.
"now my brother, papyrus... he's a human-hunting FANATIC. hey, actually, I think that's him over there."
The human looks over their shoulder, also seeing Papyrus now. He's hard to miss.
"i have an idea. go through this gate thingy. yeah, go right through. my bro made the bars too wide to stop anyone."
Sans notices the human goes along with whatever he says for now, but there's a knowing expression on their face. They still smile at his jokes and silly remarks, but through that, he keeps reading their expressions.
Are things playing out like they usually would? Besides those cues he sees on their face, Sans can't be sure.
.
Papyrus has gone on his way and Sans is left alone with the human again. Papyrus doesn't fail to cheer Sans' mood, but he still doesn't know what the human wants, exactly. It leaves him slightly unnerved.
"ok, you can come out now."
The human steps out from their hiding place behind the conveniently-shaped lamp. They don't look like they're about to leave, rather look toward Sans nervously.
"you oughta get going. he might come back. and if he does... you'll have to sit through more of my hilarious jokes."
"I'm sorry about resetting again."
Sans just looks at them in return. Even if he knows time has been altered, he doesn't have the kind of ability that lets him travel through it himself. But since this kid is apologizing to him, he must've said something to them. In another time.
He knows he's powerless against someone who can rewind time. But he also knows he doesn't remember a thing about this kid, or any "future" he might've partaken in. There is not much for him to say.
"i don't know what youre getting at, kid. anyway... hate to bother ya, but can–"
"...Can I do you a favor? Your brother has been kind of down lately. He's never seen a human before, so seeing me might just make his day."
The human finishes his sentence for him, and it makes him go quiet. They even continue after it to what Sans was still somewhat hesitating to suggest. They must've been through these same events so many times they remember in exact detail what Sans is going to say. Suddenly he feels like there's no point to engaging in conversation.
"if you already know what im going to say, there isn't much point to this."
Since they are being so straight-forward about it, Sans decides to address it. He doesn't know what to expect from this human, but they seem to know a lot about what's going to happen either way.
The human still looks troubled, now standing in front of Sans to face him.
"I don't only know what you're going to say. I know that because you ask me to cheer him up, Papyrus will make me go through a bunch of puzzles in Snowdin, then I fight him. He uses a "blue attack" that weighs my soul toward the ground. I know if I flirt with him, he'll take me on a date and then says he likes me platonically. I know he won't capture me properly–"
"...if you know all this, then you know telling me it now ultimately wont matter. because if you know all this, you've already been through it before. and though you've been through it before, you've decided to come back all the way here. to erase everything you've already experienced."
Sans pauses when the human's face is filled with shock. He continues.
"and since you've gone back at least once, i imagine youre going to do it again... since at that time i wont remember we ever had this conversation, this conversation is deemed pointless."
Through the whole explanation, Sans maintains his casual tone. He doesn't see a reason to strain himself.
"because you're someone who already knows everything i'm going to say anyway, i might as well go interact with someone who doesn't."
Irritated by this human, Sans doesn't bother to mask his teleportation. With a flash of black, he disappears.
.
He lies on his back on the mattress in his room. Teleporting such a long way so suddenly has left Sans somewhat exhausted as he stares at the ceiling, even if he had that spaghetti earlier.
If the human already knows what's going to happen, at least the polite thing to do is to pretend they don't. Oh well. Soon enough Sans' irritation would be erased again anyway, so the pointlessness of the situation descends upon him, nulling the feeling entirely.
He doesn't know if it would be worse to remember, or to keep going like this. Every time there's an anomaly, he can find out about it. Yet, he'll never be in on what has changed and why. Not in any lasting way.
At least if he'd remember, it would techically be a new experience every time. But then again... If those who rewind time would do something horrible, he'd have to keep remembering that as well.
To add, if it would be only him that has to go through this endless cycle, he wouldn't feel the same way about it. If it's only him, with no Papyrus, he could just...
No, that's probably taking it too far. It would probably take much more than that. Even if he's alone, he can't see himself resorting to that.
Speaking of Papyrus, he finds it even more annoying that the human is actually toying with his brother. They remember everything Papyrus will say and do, but keep going through it. At least Papyrus doesn't know. Sans hopes to keep it that way.
Maybe he should go keep watch on the human after all. He has other work he can do, but he prefers spending time with his brother. Even if he has to deal with that kid, too.
He peers toward the drawer where he's placed his lab key. When the human arrived, there had been a thought that occurred to him. That if they would prove themselves to be a good person, then maybe... Maybe he'd see if they could help him correct a mistake.
But if that human has gone through all those events that he thinks of as "maybes..." Clearly there really is no going back. If they were the right person to help him, they already would have.
