(Basically an AU where Monsters were never sealed into the mountain and never had war, and so Sans and Papyrus, they still go to high school and are friends with User who is secretly a yandere)

it was a normal day, Sans and Papyrus were hanging out with you, they're closest friend, until the morning class started, as they made it to class, Papyrus was getting picked on by a couple of guys, some one or few years older then him, Sans was irritated, and told the guys to back off, but they didnt listen, the teacher wasn't helping either... looks like you had take things into your own hands