This film was made because 20th Century-Fox needed a low-budget "monster movie" in the CinemaScope format to play on the bottom of a double bill with Die Rückkehr der Fliege (1959), the sequel to its "sleeper" hit Die Fliege (1958). Fox did not produce this film, however. It was made by independent producer Jack Leewood and bought by Fox.
In 1983, 20th Century-Fox produced a video game adaption of the film for the Atari 2600. It loosely follows the plot of the film, unlike some other 20th Century-Fox adaptations, which just used a film title. Though the game never saw an official release, a completed prototype has since surfaced and is available online.
Frieda Inescort's inability to overcome the challenges of multiple sclerosis was already becoming sadly apparent.
Despite having second billing, Bruce Bennett appears only in the framing scenes and not the main part of the movie.
Mrs. Hawthorne drives a 1959 Dodge station wagon.