
Revealing mistake: In the opening sequence's parody of the series where Bart becomes fat and comes out from school on his skateboard, he theoretically should go down the stairs, instead his silhouette suddenly climbs up on the wall next to him, revealing a mistake in the post-production's animation. (00:06:05)
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.