Screams echoing through a dark movie theater feed a parasitic creature that has taken root in the spinal cord and grows with fear. This blend of horror and science fiction, directed by William Castle, centers on the human body’s most vulnerable moment. A pathologist conducts experiments on a deaf and mute woman who dies of fear because she cannot scream. Black-and-white frames blend the sterile atmosphere of the laboratory with humanity’s primal terror. The redemptive power of the scream creates an unsettling tension that seeps from the screen into the theater.