The Phantom from 10,000 Leagues 1955

Name: The Phantom from 10,000 Leagues
Released: 1955-12-01
Cast: Kent Taylor, Cathy Downs, Michael Whalen, Rodney Bell, Phillip Pine

Synopsis:

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.