Devil Monster

Devil Monster (1936) is an American action-adventure horror film directed by S. Edwin Graham. The working title of the film was The Great Manta and it was shown in Great Britain as The Sea Fiend in 1938. Also, a Spanish-language version entitled El diablo del mar, directed by Juan Duval using some of the same actors and footage, was released in the United States in 1936 by Cinexport Films.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.