The cover photo of Best Buy's "Classic Sci-Fi Ultimate Collection - Volume 2" is adapted from Maggie's encounter with a man-eating squid-plant.
This story was allegedly inspired by the discovery, in 1947, of an area of inexplicably warm water in Antarctica.
This was originally set to be an expensive sci-fi epic shot in color with a large cast and Jack Arnold directing. Arnold actually began pre-production work when Universal decided to slash the budget, shoot it in black-and-white instead of color and changed (and reduced) the cast, turning it from a big-budget "A" picture to a low-budget "B" picture. Arnold withdrew from the project and Universal assigned it to one of its contract directors, Virgil W. Vogel.