J. Carrol Naish(who's best remembered by me as being in that crappy DRACULA VS. FRANKENSTEIN movie by Al Adamson) plays the lead role here as a mad doctor named Dr. Markov. We know he's evil because he don's a beard and mustache and this is the 40's. He experiments with giantism and injects a guy, whose daughter he's looking to bang, with this serum that turns him into an elephant-man-looking monster with big hands and feet and a deformed head. He also keeps a pet gorilla(classic guy in a gorilla suit) around in case anyone needs to get bumped off. As far as monster movies go this one isn't really that great since the monster never really does any rampaging up until the very very end and the plot revolves more around Doctor Markov trying to get the gal. Even the gorilla doesn't get to do very much and that's really disappointing. Luckily this is only just over an hour long and makes for a good 3am viewing on insomnia-filled nights.
Coincidentally Dr. Frankenstein is referenced in this movie and that's the character Naish would go on to play years later in DRACULA VS. FRANKENSTEIN.