Garage Sale of the Century - S1-E49
Continuity mistake: After the garage owner is cleaned out for everything he's worth, Wakko uses a remote control to drop him head-first onto the pavement. Between the following pair of shots, a cardboard 'sale' box appears on the front lawn and the owner instantly turns himself away from the garage door.
Answer: According to the Animaniacs Wikia: "Baloney is one of the few people capable of truly terrifying Yakko, Wakko and Dot, largely due to being impervious to their violently physical brand of humour and his inability to understand how much they despise him."
lionhead