The ape man, or, They creep in the dark

 Dr. James Brewster (Bela Lugosi) and his colleague Dr. Randall (Henry Hall) are involved in a series of scientific experiments which have caused him to transform into an ape-man. In an attempt to obtain a cure Brewster believes that it will be necessary to inject himself with recently drawn human spinal fluid. When Randall refuses to help him by providing the fluid, Brewster and his captive gorilla must attempt to find an appropriate donor.

Based on the story "They Creep in the Dark", by Karl Brown.