Out of the Night #21 (1953)

"Music of the Dead" tells of a strange creature awakening in Florida's Big Cypress Swamp, where a scientist and fossil expert are killed near the discovery site. A man uses a film projector to create the illusion of Satan to intimidate a follower into feeding a large mastiff creature hidden in an experiment. As the protagonist Dan investigates with Sherlock Holmes, they learn the killer sought to prevent the pterodactyl fossil discovery from becoming public knowledge, leading them to stake out the swamp hotel where the murderer plans to silence a reporter.