A pathologist, Dr. Warren Chapin (played by Vincent Price), discovers that the tingling of the spine in states of extreme fear is due to the growth of a "tingler"—a spinal parasite which can kill the host unless it is destroyed by screaming.Dr. Warren Chapin is a pathologist who regularly conducts autopsies on executed prisoners at the State prison. He has a theory that fear is the result of a creature that inhabits all of us....