Friday the 13th: The Origin of The Sound

"There was one scene where there was a close-up of Jason’s mother’s mouth going, ‘Kill her mommy,’ and then all at once it switched to little Jason’s voice saying, ‘Kill her, mommy.’ That’s the thing that gave me the idea. Most people think I’m going, ‘Chh, chh, chh,’ but I’m saying the letter k and the letter m - ‘ki’ for ‘kill’ and ‘ma’ for ‘mommy,’ see? Then I used some various voice processing. That’s actually me making that sound into a microphone."

- Harry Manfredini, composer