Giant from the Unknown (1958)

Director: Richard E. Cunha
Cast: Billy Dix, Bob Steele, Buddy Baer, Ed Kemmer, Gary Crutcher, Morris Ankrum, Oliver Blake, Sally Fraser

Synopsis:

A series of grisly murders plague a small mountain community and the sheriff suspects a local scientist whom he dislikes. Together with a former professor and the professor’s pretty daughter, the scientist sets about solving the crimes and discovers the killer is an oversized 16th century conquistador, resurrected by a lightning bolt from his mountain grave.