Trivia: This is the last episode to feature the voice of Phil Hartman, aired September 27, 1998. In it, he voices Troy McClure in a nature video about birds. Phil had been killed by his wife in a murder-suicide that May, and Troy McClure and Lionel Hutz were never replaced.
Trivia: When Homer says to Lisa "How could they change my character from cool to stupid?" and Lisa replies "creators love to tinker with shows, they drop characters, change some and push others into the background", in the background walking past the window you can see Mr. Largo and The Capitol City Goofball: two long since backgrounded characters.
Trivia: When Willie punches Professor Frink, look at the picture of Chewbacca on his shirt. If you look carefully the eyes on it move.
Trivia: At the end of the episode, when Uptown Girl has finished playing, you can hear Homer mutter under the song, 'I buried Flanders'. This is a Beatles reference as in one song John Lennon sang Cranberry Sauce and many fans misconstrued it as 'I buried Paul', as there was a rumour at the time that Paul McCartney was dead and had been replaced by a look-a-like. It's a very slick reference.
Thirty Minutes Over Tokyo - S10-E23
Trivia: During the flight to Japan, Marge reminds Homer that he had seen the Japanese movie "Rashomon" and had liked it, to which he responds something like "I don't remember it like that". This is a reference to that very movie, in which a number of people witnessed a murder and each gave a very different version of the events after what each "remembered".
Trivia: Comedian George Carlin appears in the episode as a former hippie. In "Homie the Clown", Krusty is told he's being sued by Carlin for stealing Carlin's "seven dirty words" material.
When You Dish Upon a Star - S10-E5
Trivia: Another thing "The Simpsons" predicted: Towards the end of this episode, a sign outside of a film studio shows the 20th Century Fox logo with "A Division of Walt Disney Co" written under it. Nineteen years after this episode aired, Disney purchased many assets from 20th/21st Century Fox, including "The Simpsons."
When You Dish Upon a Star - S10-E5
Trivia: At the end, Homer prank calls the "old lady from Titanic." This is Gloria Stuart, who tied with Kim Basinger (one of the main guest stars of the episode) for the SAG Award for Best Supporting Actress.
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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