The Mad Ghoul is a 1943 American horror film directed by James Hogan and starring Turhan Bey, Evelyn Ankers, and David Bruce, and featuring George Zucco, Robert Armstrong, and Milburn Stone.

Morris, who is obsessed with an ancient Mayan life-preserving process to the point of madness, has fallen in love with Allison's girlfriend, the concert singer Isabel Lewis.

Morris decides to use Allison for his eternal-life experiments, transforming him into a zombie who slowly recalls his past life, but is unaware of his undead status.

Dr. Alfred Morris is curious about the effects of an ancient nerve gas, used by the Mayans during rituals of human dissection to appease their gods.

Unbeknownst to Isabel, Morris's evil plan involves destroying Ted by exposing him to the lethal Mayan gas the next day, and in effect, making him a mindless ghoul who, like Jocko, must continually rely on the fluid of human hearts to survive (obtained by performing cardioectomies on freshly dead persons).

Eventually the police, aided by ace reporter "Scoop" McClure, realize that the mysterious "ghoul"-style killings are on the same route of Isabel's tour.

McClure tries to set a trap in Scranton, the last city of Isabel's tour, by making it seem to the public that he is someone else who has recently died, and, by waiting in a coffin for the ghoul, nearly captures Ted and Morris once they arrive to perform another cardioectomy.

She later performs for her home crowd, and Morris, in a last attempt to get Isabel for himself, sends Ted to kill "First Eric, then myself", as he constantly repeats under his spell.

[1] It began development in February 1943 with a script by Paul Gangelin and Brenda Weisberg based on a story by Hans Kraly.

[2] The director assigned to the film was James Hogan who had just signed to Universal Studios in April after seven years working at Paramount.

[3] Bruce recalled that his make-up was green and his hair was made bright red, and applied "false skin" to him, a process he described as "absolute murder".

[1][2] On June 7, a film titled Chamber of Horrors was announced by The Hollywood Reporter, noting that the cast would include Boris Karloff, Lon Chaney Jr., Bela Lugosi, Peter Lorre, Claude Rains, George Zucco and James Barton as well as the characters The Invisible Man, The Mad Ghoul, The Mummy and "other assorted monsters".