Trivia: Jesse Ventura was delighted to find out from the wardrobe department that his arms were 1" bigger than Arnold Schwarzenegger's. He suggested to Schwarzenegger that they measure arms, with the winner getting a bottle of champagne. Ventura lost because Schwarzenegger had told the wardrobe department to tell Ventura that his arms were bigger.
Trivia: This movie was originally supposed to be part of the TV series "Amazing Stories" but Steven Spielberg like the story so much that he decided to make it a full length film.
Trivia: The filmmakers used two different shopping malls for the scene where the doctor injects Tuck into Jack's rear. The opening scenes where the doctor runs in and heads for the elevator were shot in the Northridge Mall in the San Fernando Valley in Los Angeles. The scene where he reaches the top and rams the syringe into Jack was filmed on the top floor of the Sherman Oaks Galleria, another mall several miles away.