Trivia: The film's original title was "Red Rain" and the Peter Gabriel song of the same name was meant to be featured in the film. However, they couldn't get the rights to feature the song, so the song "Red Harvest" was commissioned and written specifically for the film. Shortly before the film's release, the studio decided that the title "Red Rain" no longer made any sense without the Gabriel song in the movie, and instead retitled the film "Jack's Back."
Trivia: The demon effects were done by Carlo Rambaldi, who is arguably most famous for creating the design of the benevolent titular character from Steven Spielberg's "E.T."