Continuity mistake: In "Wiz Kids", Bart stabs Montymort in his shin which is open (i.e. not covered by what he's wearing). Only a little blood pours out. Then Monty raises his shin into shot and there is not only a puncture in the leg of his clothing, but the wound is covered in blood. When he falls, and Slithers eats him moments later, there is no damage at all.
Continuity mistake: At the end of 'Wiz Kids', when Lord Montymort is defeated, he falls to the floor, breaking all the floorboards. Then when Lisa takes off the headset, all the floor is intact. In the next shot, the floorboards are all broken again.
Continuity mistake: After Homer's father, Abraham, comes home after a night out with Zelda, Homer snatches his keys away from them. He leaves his hand out and begins outstretching fingers one by one to represent all the people he called in worry, and it's clear that the keys have disappeared.
Continuity mistake: In the cinema, it is clear that the people attending the movie keep on changing. For example, For a few shots, you can see that Krabappel and Skinner are sitting in the front row, but the next time you see those seats, they have been replaced by Lenny and Carl and Krabappel and Skinner aren't in sight.
Continuity mistake: When Marge and Homer are at the Springfield formal ball at the Country Club, about half way through the ball, there is a woman with her back to the camera as she is talking to Marge and Homer. Homer is on Marge's left side. In the next shot when Marge's back is to the camera and you can see Marge still talking to the woman, Homer is no longer on Marge's left side, he is gone.
Continuity mistake: When Bart is in the ice cream parlor breaking up with Greta, the waiter tells him "We get that a lot around here" and point over to Chief Wiggum and Lou sitting behind and to the left of Bart. Bart turns his head all the way to the side to see them. The focus then goes to Chief Wiggum and Lou, but when their part is done and the "camera" goes back to Bart and Greta, the policemen are sitting behind and to the right of Greta, so that Bart would not have had to turn his head to see them.
Continuity mistake: The stocks that are put on Marge and Homer are fitted so that their head and hands are secured and cannot be removed. Whilst in Flanders garage and Homer is using the rotary saw to remove Marge's stock, Homer's stock is still secured on him but his arms and shoulders are through the stocks.
Continuity mistake: In one of the shots after Mr Burns has broken the fortune cookie, the remains of it vanish from the table. There is something else on the table, nearer Smithers, but it and the cookie are very different shapes, so it's very difficult to confuse the two.
Add timeDavid Mercier
Continuity mistake: At the end of 'Hex and the City,' there is a shot of the wedding cake, then it pans across the people at the wedding, and you can see Homer with his white shirt on. But then when it goes to a closeup, he suddenly has a blue suit and tie on.
Continuity mistake: At the show the school puts on in "Wiz Kids", when the Montymort Dragon is first seen in the cage, the cage has 6 bars at the front. When Lisa says "Release The Dragon", the cage has 4 bars. When the cage door is being raised, it has 6 bars again.
Continuity mistake: In "House of Whacks", when Marge opens the door to the robotic salesman, you can see there is a green mat under the door. But when the salesman puts his foot between the door, the mat is missing, and in next shot the mat has re-appeared.
Continuity mistake: In "Hex and the City", when Homer, Bart, Lisa and Maggie are eating their breakfast at the table, they see Marge with a blue beard and Homer spits some food on the table. In the next shot, the food has gone, and when Homer goes to strangle Bart, it is back again.
Continuity mistake: In "Hex and the City", when Marge, Bart and Lisa are at the Fortune Teller's office, you can see the Fortune Teller has three cards in front of her on the table. When Homer arrives, the cards have gone, and later on in the scene they are back on the table again.
Continuity mistake: At the end of the episode when Bart, Lisa and Maggie greet their parents Bart says that they were in the Green Room (a room where the cast of a show can relax when not performing) and comments that '[he] ate so much shrimp!' This conflicts with the episode 'Please Homer, Don't Hammer 'Em', where it is revealed that Bart is allergic to shrimp.