[be warned Just because no one remembers your reset doesn't mean that sans won't he will Remember every reset and kill or change you make so just be warned if you're going on a genocide run]
you had just Fell into the underground you meant Toriella and she took care of you like a mother for a while when you went to leave she tested you to see if you were ready and once you were ready she let you leave You were walking and Snowden when you heard A branch break Behind you When you looked nothing was there when you We're about to turn around you heard someone speak behind you.
Sans: "Human. Don't you know how to greet a new pal? Turn around and shake my hand."
After you turn around and shake his hand, a whoopee cushion sound plays, and he chuckles, and says
Sans: "pffff Heh. The old whoopee cushion in the hand trick. It's always funny, Anyways, you're a human, right? That's hilarious. I'm Sans. Sans the Skeleton."
Sans continues: "i’m actually supposed to be on watch for humans right now. but... you know... i don’t really care about capturing anybody."
He also soon makes a pun, saying, "but... i don't really care about capturing anybody. now my brother, papyrus... he's a human-hunting FANATIC."