The Thing that Couldn't Die is a 1958 American horror film about a man executed for sorcery 400 years in the past whose detached head hypnotizes people in order to have them reunite his head with his body so he could live and feast on the blood of people. It was produced and directed by Will Cowan and starred William Reynolds, Andra Martin, Jeffrey Stone, and Carolyn Kearney. Based on an original screenplay by David Duncan for Universal Pictures, it was released in the United States on a double bill in May 1958 with the British Hammer Films classic Horror of Dracula.

Plot

Jessica Burns (Carolyn Kearney), a young woman who claims to have psychic powers, lives on a California dude ranch with her Aunt Flavia (Peggy Converse). When Jessica is called upon to dowse in search of a groundwater spring, she instead discovers a buried box dating from the 16th century. Against Jessica's warnings, Flavia takes the box back to her house. Flavia, consumed with thoughts of buried treasure, wants to open the box immediately. But Gordon Hawthorne (William Reynolds), a guest at the ranch who has shown interest in Jessica, argues the box should be kept intact for appraisal. That night, he leaves the ranch to bring an archaeologist friend to inspect the box.