Treehouse of Horror XIII - S14-E1
Continuity mistake: The beers Homer puts under the hammock vanish when the hammock breaks, and Homer falls to the floor. (00:01:15)
Treehouse of Horror XIII - S14-E1
Continuity mistake: When Homer starts to strangle his clone, the clone throws the boxes it was carrying, to the floor. In a following shot the boxes have vanished. (00:04:20)
Treehouse of Horror XIII - S14-E1
Audio problem: When Homer is playing the piano, and Marge is playing the cello, Frink grabs Homer and pulls him into the room. However the playing of the piano continues, even after Homer is pulled away. (00:13:50)
Treehouse of Horror XIII - S14-E1
Continuity mistake: The people standing to the left of the rock, as the Comic Book Guy (as a faun) walks onto it, changes. In the first shot the police officers and Raplh stand there, in the second shot it's a panda. (00:19:25)
Treehouse of Horror XIII - S14-E1
Continuity mistake: When everyone has been turned into animals, Police Cheif Wiggum, as a pig, takes off his tattered shorts and throws them into the fire. Later in the scene he's magically wearing them again. (00:19:40)
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.