Continuity mistake: When Ned is saying grace, the plates on the table contain no food, but when Homer comes through the window there's food on the plates.
Revealing mistake: When the man with the white helmet and flashlight asks Homer if he's holding on to the can in the vending machine, a large scratch appears near the upper right corner of the screen over the man's helmet.
Continuity mistake: When the robber shoots Apu, he is shot around his leg. In the next shot, the wound is in his chest.
Tree House of Horror IV: The Simpson's Halloween Special IV - S5-E5
Other mistake: When Bart says the picture of the school bus is actually called The Ghoul Bus, Lisa points out the name tag says The School Bus. If you closely at the name tag, you can see nothing is written on it.
Tree House of Horror IV: The Simpson's Halloween Special IV - S5-E5
Continuity mistake: When Otto hits Hans Moleman's car, it has a number plate on it, which disappears when he crashes.
Tree House of Horror IV: The Simpson's Halloween Special IV - S5-E5
Continuity mistake: Just before Homer is sucked into Hell, he is wearing pyjamas. When he's in Hell, he's wearing his usual day clothes.
Continuity mistake: During the wedding you can see in the background Apu and Sanjay but Sanjay's skin is yellow.
Cape Feare - S5-E2
Continuity mistake: When Bob is working out on the weights, he has a tattoo of something on his knuckles, but when he is watching the exercise video, the tattoo dissappears.
Bart Gets an Elephant - S5-E17
Continuity mistake: Immediately after being chained to a tree, Stampy crushes several objects (a lawnmower, a bike, a doghouse, and a trash can). In the very next shot, which comes after a commercial break, all of these objects are in fine shape. Then the shot changes again and we see them destroyed once again. (00:09:30)
Other mistake: When somebody throws a cola can at Homer, the can never hits the ground.
Homer's Barbershop Quartet - S5-E1
Continuity mistake: When Bart and Lisa find the record Melvin and the Squirrels, they hand it to the Comic Book Guy to play. While the record is in his hand you can still see it displayed on the rack.