

A Satanist cult leader is burnt alive by the local church. He vows to come back to hunt down and enslave every descendant of his congregation, by the power of the book of blood contracts, in which they sold their souls to the devil.
Acting
Ernest Borgnine's unhinged Satanist priest performance deserves an Oscar in Hell.
Practical Effects
The melting effects are genuinely horrifying and physically revolting.
Costume
Goat-men robes that look stolen from a community theater production of Macbeth.

Director
Robert Fuest
Trivia, insights & behind the scenes
Anton LaVey, founder of the Church of Satan, served as technical advisor and appears as the High Priest.
This film essentially ended William Shatner's theatrical leading man career—he didn't headline another feature for years.