As famous for the gimmick with which the film was shown as for its genuinely spine-tingling story, The Tingler follows a pathologist (Vincent Price) as he searches for the cause of a series of deaths and discovers that the victims have a large insect-like creature growing on their spinal chords. The creature attacks when the people are frightened and is only killed when the host emits a blood-curdling primal scream. This is coupled with a subplot to scare the deaf-mute owner of a silent movie house to death. Along the way, a couple of characters are injected with LSD and begin hallucinating like mad. When one of the nasty monsters "escaped" into a movie theater, the film's gimmick would begin. In order to further frighten audiences, director William Castle had certain theater seats rigged with small Army surplus devices that would deliver a mild electric shock to the spine in hopes of inducing terrified screams.