The Phantom from 10,000 Leagues

The Phantom from 10,000 Leagues (1955) is a horror, science fiction directed by Dan Milner rated 4.2/10.

A marine biologist and a government agent investigate mysterious deaths and rumors of a sea monster in a secluded ocean cove, and find themselves involved with a marine biology professor conducting secretive experiments, international spies trying to steal his secrets, a radioactive light on the sea bottom, and the malevolent thing which guards it.