A college paleontology professor acquires a newly discovered specimen of a coelecanth, but while examining it, he is accidentally exposed to its blood, and finds himself periodically turning into a murderous Neanderthal man.
Arthur Franz
as Donald Blake
Joanna Moore
as Madeline Howard
Judson Pratt
as Lt. Mike Stevens
Troy Donahue
as Jimmy Flanders
Nancy Walters
as Sylvia Lockwood
Helen Westcott
as Nurse Molly Riordan
Ross Elliott
as Sgt. Eddie Daniels
Alexander Lockwood
as Prof. Gilbert Howard
Whit Bissell
as Dr. Oliver Cole
Richard H. Cutting
as Tom Edwards - Forest Ranger
Hank Patterson
as Townsend - Night Watchman
Phil Harvey
as Sgt. Powell
