---SPOILER ALERT---
If you're into Undertale (or if it interest you) but don't know what's happening in the Genocide run,plz don't read!
---YOU'VE BEEN WARNED---
In the genocide run we have to fight Sans to death...And since you killed all his friends and more importantly his brother he's going to avenge them but before you fight Papyrus at the start he made a promise that if you kill his bro you're gonna have a bad time...So...Yas...