Written by: Robb White
Starring:Vincent Price, Judith Evelyn, Darryl Hickman, Patricia Cutts
A coroner played by Vincent Price discovers that fear causes a creature to grow on a persons spine. He discovers this during an autopsy on a deaf-mute girl - Judith Evelyn - who has died from fright (should have bought insurance). Price captures the creature, but it gets loose in a theater, presumably the one where you are viewing the movie. Lots of experiments, a bad LSD trip (the films only color sequence) and screaming make this a classic thriller. This is probably the best known of Castle's films due to his creative use of a gimmick he called Percepto (see below). Some nice clips are available on YouTube.
Percepto - This effect involved rigging selected theater seats with a vibrating buzzer unit under the seat. At predetermined times during the film the projectionist would set off these "tinglers", resulting in lots of screaming. A special crew traveled the country setting up theaters for this effect.
In all William Castle estimates they probably buzzed 20,000,000 bottoms through the full run of this film in theaters. Also of note - Judith Evelyn must hold the distinction of being the only Castle movie heroin NOT to scream.