Continuity mistake: When the family are watching Krusty Komedy Klassics, at the beginning of the show, they all have grey tables, with their dinner. But when Bart asks for milk, Marge gets up to get it and her table has disappeared. When she comes back the table has re-appeared.
Continuity mistake: When the Ranger stops the Simpsons' car at the start of the episode, watch his "class ring". When he puts his hands inside the car it's on the left hand. However, the flies later eat his hand and take his ring, and it's suddenly his right hand they ate and took it from.
Add timeDavid Mercier
Continuity mistake: When Bart gets on the bus, we see one of the twins sitting near the front of the bus. In the next shot, we see both twins sitting at the back. The shot after that, we see the twin near the front again, running to the back.
Continuity mistake: When the store is being robbed, Homer throws his bag to the side and it lands face down near the stand of chips Homer jumps into. But when they are watching the video of this incident later, the bag is standing upright, far away from the spot it previously was at.
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: By the vending machine, Lisa first points her card at the cell on the right, then there's a zoom on the cells and we see her hand starting to point again, but this time at the cell in the middle. In the next shot, she lowers her hand with the card, which however in this shot is pointing at the cell on the right again.
Continuity mistake: Homer is on the front lawn when the bus of tourists turn up and Mario comes out. Homer gets mad and throws trash cans at Mario, who runs away and climbs up into the tree house which is at the side of the house, but it should be at the back.