Barbara Hershey plays a single mother who is repeatedly sexually assaulted by an invisible force. I was impressed with how brutal and explicit the attacks are, right down to some creepy special effects that simulate the squeezing of Hershey’s breasts by unseen hands. Though the rapes are supernatural, they’re among the most terrifying I’ve seen on film, due largely to Hershey’s fearless performance. The final act tries too hard to explain things, conjuring up a hokey scientific experiment for the climax — but up until then, I gotta say, for what is essentially a ghost story, I was pretty creeped out. Directed by Sidney J. Furie (The Leather Boys).