Allegedly, Peter Lorre was so appalled by the script that he immediately fired his agent for trying to get him a part in the movie.
There is an actual hot air balloon that resembles the She-Creature's head. Fondly referred to as "Cuddles" by fellow balloon pilots. This balloon has been use to promote TNT's Monstervision (1991) television show.
The dog that walks along the beach with Marla English is, in real life named Spike, and is the same dog who played the title character in Old Yeller (1957).
Paul Blaisdell's creature suit was reused in several other American International films, including Voodoo Woman (1957) and Ghost of Dragstrip Hollow (1959).
The story was inspired by the success of the best-selling book The Search for Bridey Murphy, which concerned hypnotism. Exhibitor Jerry Zigmond suggested this subject might make a good film, and AIP commissioned Lou Rusoff, brother-in-law of AIP executive Samuel Z. Arkoff, to write a script.