you wanna have a bad time

usually, if you hear this in undertale, you should probably run.

hey. let me ask you a question. do you wanna have a bad time?~Sans 201x

You wanna have a bad time?

This is something that the character Sans from undertale says. He says this if you pick the genocide rute by killing the other monsters. When he says this is when you meet him in a hall.

Frisk: Hi Sans.
Sans: You wanna have a bad time?