Creature of the Walking Dead is a 1965 horror film re-edited by Jerry Warren from a 1961 Mexican horror film La Marca del Muerto, which translates as Mark of the Dead Man. The original Mexican film was directed by Fernando Cortés, written by Alfredo Varela Jr., and released in Mexico on October 12, 1961. The special effects was handled by Nicholas Reye.

Dr. Malthus (Fernando Casanova), a 19th-century mad scientist, discovers the secret of eternal youth by means of draining the blood of young women into his subjects. He is hung for his crimes, but his grandson (who looks just like him) inherits his home and revives him from the dead. Malthus then resumes his rejuvenation activities using himself as the subject and enabled by the grandson, who procures healthy young victims they can bleed. Fernando Casanova played both the mad scientist Dr. Malthus and his grandson in a dual role.

Warren’s contribution to the U.S. version of the film consisted of extensive editing, some dubbing of the Mexican players in select scenes, voice-over narration over most of the Mexican footage, and the inclusion of several brief scenes filmed by Warren in the United States with American actors. The Americanized version was released on June 15, 1965.

Warren wrote actor Bruno Ve Sota into the film as a police inspector in the added American footage, and added some scenes starring Katherine Victor as a fortune teller conducting a seance. Although a “Rock Madison” was given top billing in the credits, modern sources state that “Rock Madison” was just a fake name made up by Jerry Warren to make his casts seem larger.