Body Snatcher

LADRON de CADAVERES-1957-Strange Mexican horror film has a mad scientist Don Panchito (Carlos Riquelme) experimenting with the dead bodies of atheletes and apes in some kind of brain transplant to conquer death. A police captain Carlos Robles (Crox Alvarado) recruits a luchador named Santana (real wrestler Wolf Ruvinskis) to help him set a trap but the wrestler dies in the ring from poison administered by the scientist's henchman. 

The detective's  friend Felipe(Arturo Martinez), who for most of the movie is romancing the detective's secretary, disguises himself as the dead wrestler but is killed and turned into a super strong monster with the brain of a gorilla! Naturally the scientist sends his creation into the ring where kills his opponent and runs amuck as the crowd panics. The creature transforms into an ugly hairy man beast with fangs. He impales the scientist on  hook (great bloody scene) then kidnaps the secretary after a lot of climbing. He's shot by the police and falls to his death.

The director Fernando Mendez went on to make other horror movies like EL VAMPIRO and THE BLACK PIT OF DOCTOR M. Wrestler Wolf Ruvinskis created the superhero Neutron and played the lead in several movies featuring the character. Co-star Martinez was later in the Aztec Mummy series.

Thanks for reading!