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.

An edited version of the film was released in 1946 as Devil Monster, a low-budget South Seas drama spiced up with stock footage inserts including half-dressed native girls who were also featured in the film's trailer. The Hays Code, which banned nudity in American films, apparently tolerated partial nudity in "ethnographic" scenes of "native" life. This version of the film is now in the public domain and is available online at Internet Archive.