Trivia: Gromit was originally supposed to be a cat, but it was decided that a dog was easier to sculpt from plasticine.
Trivia: After Sylvester has swallowed the bowling ball, he goes back down the drainpipe and out into the street. When this happens, look behind him and you can see a sign saying "Drink Friz! Six Delicious Flavors" - a reference to the director Friz Freleng. There is also a building with "Champin's 5 and 10" on it - a reference to the animator Ken Champin.
Trivia: Just after Linus seals his letter to the Great Pumpkin in an envelope, he walks past Lucy who is sitting on the floor watching TV. In her hands, Lucy is holding an issue of TV Guide Magazine. On the cover? Lucy, sitting on the floor in the same position, wearing the same blue dress. (00:07:00)Professor Zed
Trivia: When Elmer finds himself in the year 2000, he picks up a newspaper with a headline saying "Smellevision replaces Television!" Underneath this there is a caption saying "Carl Stalling sez, "It will never work!" Carl Stalling was the music composer and arranger for the Looney Tunes and Merrie Melodies shorts produced by Warner Brothers.