This is truly one of the better "Slasher" movies from the 1980's, featuring crazy-eyed Joe Spinell as a serial killer. In an opening scene he kills a couple on the beach, then kills and scalps a prostitute in a hotel room. What he does with the scalps is put them on these creepy looking mannequins he has in his apartment. Of course, he also has Mommy issues and constantly brings her up in conversation.
Caroline Munro shows up halfway through the movie as a fashion photographer Anna who befriends him, not realizing what a loon he is. However, on their way to dinner one night they make a side trip to the cemetary where his mother is buried and he flips out and tries to kill her. She gets away, though he's injured. Back at his apartment, while he's laying in his bed, the bloody headed mannequins come to life and rip him to shreds. However, when the police break in, presumably called in by Munro, they see that he has simply bled to death from his wound.
Joe Spinell gives quite a believable performance here, though I'm not so sure I buy it that the Munro's Anna character would be remotely interested in him. What's really worth checking out are all the early Tom Savini makeup effects. MANIAC remains on my top ten list of favorite serial killer movies.