Co-star Robin Hughes would often perform Shakespearean monologues between shots. His horror makeup would enhance these moments all the more.
Shot in just two weeks in early 1958.
The original title of the film was "The Water Witch". Later, when the studio suggested a different title, "The Thing That Couldn't Die" was suggested by marketing and won out. The person who thought it up received $50.
The Thing That Couldn't Die was shot during a slump period for Universal. The studio cut back heavily in the late 50s, and this low budget production was shot in the nearly deserted studio lots.