Continuity mistake: When Bart and Laddie are at the Springfield Town Hall, you can see there is nothing on the wall behind them, but in the next shot a plaque appears.
Continuity mistake: When Bart is talking to Milhouse in the park, there are two pine trees in the background. When we see the two a little later, the pine trees have gone.
Continuity mistake: When the man in the park throws a Frisbee for Laddie to fetch, the Frisbee can be seen falling to the ground, but when we see Laddie running, the Frisbee is back in the sky again.
Continuity mistake: When Laddie is eating the meat that Bart gave him, Santa's Little Helper's bowl is next to his bowl. When we see Laddie two shots later, there is now only one bowl, and in the shot after that, there are two bowls.
Continuity mistake: When Bart asks his mother if he could feed Laddie during the dinner scene, he has a glass in front of him on the table. But when we see Laddie eating, Bart's glass has gone.
Continuity mistake: Marge is holding a leaflet containing Laddie's instructions when Homer wonders where the dog is, but when Laddie returns, she no longer has the leaflet.
Continuity mistake: When Homer says "Where did he go?" when Laddie wanders off, Marge is standing in front of an archway. In the next shot, she is standing in front of a cabinet.
Continuity mistake: There is a latch on the crate when Bart opens it and Laddie appears, but when Laddie jumps out of the crate, the latch has gone.
Continuity mistake: When Bart opens the door and finds the crate containing Laddie, there is nothing on the doorstep but in the next shot a green mat appears.
Continuity mistake: When Lisa comes into Bart's bedroom, the number of balls in the bottom tray of the bagatelle game increase between shots.
Continuity mistake: When Bart sees "The Covet House" order in the catalogue he has picked up from the trash can, he is reading it with both pages open, but when we see him in the next shot, he is reading the catalogue with the back pages folded under.
Continuity mistake: When Bart is at the Card Shop, he picks up the magazine "Zoidzilla" and put on the top of the pile he is holding. But when he takes the pile to the cash desk, The Front cover of the magazine is now coloured green.
Continuity mistake: When Marge discovers a letter for "Santos L. Halper", Bart has nothing in front of him on the table. In the next shot, a knife, fork, bowl and glass have appeared.
Continuity mistake: When we see Bart holding the post, he is initially holding it with one hand, but when we see a close-up of the post in the next shot, he is holding it with both hands.
Continuity mistake: When Marge finds Lisa's German verb wheel in the post during the breakfast scene at the start of the episode, you can see Lisa has nothing in front of her. In the next shot, a bowl and a glass have appeared.
Tree House of Horror VII - S8-E1
Continuity mistake: In "Citizen Kang", when the alien whips Marge's behind, you can see in the background there is a tree that changes to a crane in the next shot.
Tree House of Horror VII - S8-E1
Continuity mistake: In "Citizen Kang", when Homer pulls off the masks off the fake Clinton and Dole at the White House, the two transform into aliens and you can see Homer is between them. In the next shot, Homer is missing, and in the shot after that, he is back again.
Tree House of Horror VII - S8-E1
Continuity mistake: In "Citizen Kang", when Homer tries to save Clinton and Dole in the spaceship, Homer is standing behind a control panel and you can see there is nothing on left of it, but in the next a large lever suddenly appears.
Tree House of Horror VII - S8-E1
Continuity mistake: In Citizen Kang, when Kang and Kodos (as Clinton and Dole) are speaking to the man from the Democratic National Committee, you can see the building in front of them has a plant outside and there are shades on the windows. But when Homer appears in the next shot, the plant and shades have gone.
Tree House of Horror VII - S8-E1
Continuity mistake: In "Citizen Kang", when we see the family eating breakfast at the table, you can see that Bart has a bowl in front of him. But when Homer comes into the kitchen, there is now a glass by the bowl, and in the next shot the glass has gone again.
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.