Continuity mistake: Abe's girlfriend dies in the middle of this episode, but at the end, seconds before the end credits, you can see her walk behind some other old people.
Continuity mistake: In the scene where Lionel Hutz hands over the $106 check, Abe Simpson's room number is 18. After Abe called Homer, the manager of the Retirement Castle comes in. The number 18 has now disappeared.
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.