Continuity mistake: Marge said to Bart she would make Butterscotch chicken for him, but in the Season 2 episode "Blood Feud" Marge says Bart's allergic to butterscotch.
Continuity mistake: When Homer is sitting in the Frying Dutchman with the crowd gathered round looking at him, the Captain invites people in. Some start walking in, but in the next shot where they are all gathered round again, it is the same group of people again.
Pygmoelian - S11-E16
Continuity mistake: At the start of the episode, Homer wakes the family up and they get in the car in their night clothes. When they arrive at the destination, they are dressed.
Ssiscool
Continuity mistake: After Selma gives Madam Wu the sack of ten thousand "happinesses" the sack instantly vanishes from off the table. (00:08:40)
Hamster
Tree House of Horror II: A Simpsons Halloween - S3-E7
Continuity mistake: When Jimbo and Kearney take Homer's candy, it is obviously night time. However if you watch the outside as Homer closes the door before he says "Lousy punks" it shows a daytime sky.
OL1V3R666Continuity mistake: After Bart and Milhouse drink the all-syrup squishee, the syrup disappears from Bart's face between shots.
OL1V3R666Bart's Friend Falls in Love - S3-E23
Continuity mistake: At the beginning of the episode when Bart runs away from Homer, Homer starts rolling down the stairs. The banister disappears between shots. After Homer gets to the bottom the banister reappears.
OL1V3R666Burns' Heir - S5-E18
Continuity mistake: When Smithers finds Burns drowning in the bathtub, he throws the rag. When the rag hits the floor, it magically disappears.
Dr WilsonContinuity mistake: When Homer is taking the kids to school for the second time the view behind him doesn't look further away while driving.
OL1V3R666Brake My Wife, Please - S14-E20
Continuity mistake: When Hibbert handcuffs Bart to the radiator, for one brief second, his cast and bandages disappear. They return in the next shot.
SexyIrishLeprechaunSweets and Sour Marge - S13-E8
Continuity mistake: When Homer falls off the human pyramid, he grabs onto someones rear end to stop himself from falling. In the next shot, he is suddenly holding a foot.
David MercierContinuity mistake: When Homer opens the door on Bart the door handle is purple with a grey backing. Later when Homer is saying 'If I went to a BBQ and there's no meat...' there is only the purple knob.
Continuity mistake: When Lisa is standing outside the Kwik-E-Mart, the "open 24 hours" sign on the window changes position between shots. (00:13:00)
jleHomer Alone - S3-E15
Continuity mistake: In the scene where Maggie rips of the top of her bottle, the milk spills everywhere, including on Marge's face. After this Marge goes really crazy and starts screaming. Right before she does this the milk on her face disappears.
Continuity mistake: Before Homer and Marge get married, they are taking more steps then they are supposed to, as you can see the interior of the wedding chapel before this scene. (00:10:10)
Yoshi
Burns Verkaufen der Kraftwerk - S3-E11
Continuity mistake: At the beginning, Mr. Burns pats his alligator, and his hand is instantly down in the next shot. (00:01:50)
YoshiContinuity mistake: Patty sprays Barney with pepper spray. It disappears from her hand in the next shot. (00:18:55)
YoshiContinuity mistake: At the end, when Bart gets his trophy, Marge and Homer switch positions. (00:20:35)
YoshiContinuity mistake: Homer drives to Moe's Tavern with his normal shirt on. He has his green jacket on top of it in the next shot. (00:04:45)
YoshiContinuity mistake: In the video store, Homer grabs the 'Football's Greatest Injuries' tape with his right hand. He was also holding Maggie with his right arm, so he should have dropped her. (00:06:00)
Yoshi