The Black Pit of Doctor M.
(Misterios de ultretumba)

An asylum is run by three doctors. One of the doctors dies promising to return to explain the mysteries beyond the grave. Dr. Mazali contacts his dead colleague through a medium. The doctor returns with disastrous results for all, including murder, mutilation, the unjust execution of Dr. Mazali who also arises from the grave in the body of a man who has been facially disfigured by acid.