Used Car/Bounty Hunters - S8-E9
Continuity mistake: In "Used Car", when Beavis and Butt-head first approach the car, it's in between two trucks, a white one and a brown one. At the end, the spot where the car was is now between a green car and the white truck.
Beavis: Hey Butt-head, is it normal for the inside of your bunghole to itch?
Butt-head: Beavis, it's not even normal to ask.
Trivia: Mike Judge once received an angry phone message from a fast-talking man. The man seemed to be complaining about "Beavis and Butthead", although he mentioned a "Porky's butthole". His voice later inspired the voice for Boomhauer on "King of the Hill".