Days of Wine and D'Oh'ses - S11-E18
Continuity mistake: When Moe tells Homer to sit on Barney's seat in front of the beer tap, Homer is sitting on a stool next to it. Homer suddenly switches seats between shots and the other seat disappears.
Days of Wine and D'Oh'ses - S11-E18
Continuity mistake: The police car door doesn't appear on Barney's arm until they watch the video.
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.