Before there was A Nightmare on Elm Street, before Alien there was "The Tingler" (1959). A parasite that attaches to your spine causing hallucinatory nightmares that kill you. It grows stronger when you are afraid. This film is a classic from the mind of horror director/producer William Castle. When the film came out there was also a device attached to seats in some movie theaters called Percepto! which when activated by onscreen action violently vibrated your seat.  Some theaters also gave audiences Death Certificates  in their name telling how they died of fright.
How cool is that?