Other mistake: While Homer and Moe are in the treehouse, Homer suggests to Moe that he propose to Maya. As their conversation continues, Homer's left hand doubles, so he has two left hands. Then, when Moe tells him he'll give it a shot, the fuzzy part of Homer's green slipper is missing.





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.
Xofer