The Twisted World of Marge Simpson - S8-E11
Easter egg: On disc 2 of season 8, highlight episode menu for "The Twisted World of Marge Simpson", then press up to select the button on the projector; this will access a hidden deleted scene featuring "the Investorettes".
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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