I term meaning "You are fucked" or "There's no way out". Often applied to non-severe issues such as a flat bike tire. However, it can also be used to taunt a friend when they encounter an legitimate reason to worry.
Another use implies threat.
Use 1
Person 1: "Dude, that ugly girl asked me out and I was so drunk I said yes!"
Person 2: "You're done son."
Use 2
Person 1 spills hot coffee all over some douche bag at the food court.
Ruler of Lake Titicaca. Rumored to have a bunghole that gets very angry if it does not receive toilet paper. Cornholio the Great is often seen walking around with his shirt over his head and his hands in the air, chanting songs about his power, and his bunghole.
"I am Cornholio! You do not want to face the wrath of my bunghole, for I need TP!"
Butthead: Shut up, Beavis! (uh huh huh huh)
Beavis: Um, okay. (heh heh heh heh).