Continuity mistake: When Beavis is getting the idea to use the plate as a discus, the amount of cookies on the plate varies depending on the shot.
Beavis and Butt-head vs. the Vending Machine - S4-E28
Continuity mistake: When the woman is closing the door to the women's restroom, the doorknob briefly changes from gold to gray.
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".
Crisis Line - S4-E27
Question: Why did Mr. Van Driessen only give Beavis and Butt-Head one phone?