Radio Bart - S3-E13
Continuity mistake: When Homer, Marge and Sting are down the hole and Sting is digging, Homer is wearing a vest. But in the next shot when they find Bart and Homer moves Sting out of the way, he is wearing a shirt. (00:20:50)
Radio Bart - S3-E13
Audio problem: Just after Krusty kicks Sideshow Mel into the big birthday cake on his show, he says "Hey kids" but his mouth doesn't move right.
Continuity mistake: At the start, the remote on the sofa next to Homer simply vanishes and returns when Marge walks in. (00:00:40)
Continuity mistake: When Homer is eating the snacks at the start, he drips some dip on the sofa that vanishes when Marge appears. (00:00:50)
Continuity mistake: At the start, the design on Homer's beer can change. Note the white stripe. (00:00:55)
Continuity mistake: When Homer gets off the phone to Moe, all the snacks he had have simply gone beyond a few remaining bits. (00:02:00)
Continuity mistake: When Homer is yelling at the TV about being wrong 48% of the time, the colours of his beer can are reversed. (00:03:40)
Revealing mistake: When the announcer says that the Falcons win, he says "Who would've thunk it" Homer says "My daughter, that's who". When he is saying this, Lisa's arm disappears twice. (00:10:05)
Continuity mistake: When Lisa is lying on the floor, she has 3 pieces of paper/notepads with her. Once she starts to ring Moe though, there are only 2 pieces of paper on the floor. (00:12:05)
Continuity mistake: Just as Barney asks Homer if he wants to go bowling next Sunday, Moe's boot disappears from the bar and the money appears in Homer's hands off the bar. (00:12:20)
Continuity mistake: When Homer goes to apologise to Lisa, he walks into her room and leaves the door open. As he steps inside however the door is now closed. (00:15:50)
Continuity mistake: Homer picks up Lisa who puts her Malibu Stacey down on the bed. When Homer puts her down, the doll and house have disappeared. (00:16:30)
Continuity mistake: At the bar when Homer is watching the superbowl, his hands keep changing position between the shots. (00:19:00)
Revealing mistake: When Homer leaves the bar after the Superbowl, as he goes through the door, the background is missing. It's just a brown background. (00:20:00)
Continuity mistake: Homer goes to ring the phone number '1-909-WIN-BIGG' but we see he only presses four dials, and that's all we hear too.
Homer Alone - S3-E15
Audio problem: At the start in the kitchen when Homer, Bart and Lisa are all talking over each other, their mouths don't match what they're saying. (00:02:30)
Homer Alone - S3-E15
Audio problem: When Lisa screams "Mom" on the way to school, she just leaves her mouth open and doesn't close it. It should sound like "Maaaaaa" if she keeps her mouth open. (00:03:20)
Homer Alone - S3-E15
Audio problem: When Marge is running errands, Homer gives her his bowling ball with a bottle cap stuck in a hole. She then takes it to Nicks. When he says, "Sorry lady, you've got the wrong Nicks," he shakes his head and makes an "Ohh" shape with his mouth, not saying anything. (00:03:50)
Homer 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. (00:04:50)
Homer Alone - S3-E15
Deliberate mistake: Arnie says that he drops his bagel. When he does he starts to say it, but when we see the helicopter it has just fallen out. If he dropped it at the time he did, then it would be much further down and wouldn't be visible in that shot. (00:05:20)
Answer: I'm not sure if this is the one you're thinking of, but an episode of "Ray Bradbury Theatre," called "A Sound of Thunder," dealt with a similar matter: a group of hunters travel back in time to hunt dinosaurs, only to find things have changed when they get back because someone stepped on a butterfly.
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