Deafula is a 1975 American horror film done completely in American Sign Language. A voice over is provided for those who do not understand sign language. The film starred Peter Wechsberg, who also serves as director and writer, under the pseudonym Peter Wolf. It was the first American Sign Language feature film ever made. The film tells the story of a young man who cannot control his urge to kill people for their blood, and the police investigation searching for the murderer.