For nearly half a century, one eerie sound has been showing up again and again in movies and TV shows. It’s typically used when something spooky or mysterious happens—and it can be heard in Poltergeist, The Matrix, Let the Right One In, and countless episodes of Unsolved Mysteries. So where did this strange sound come from, and how did it spread across Hollywood? This story comes from the podcast Every Little Thing. We’ve been nominated for 2 Webby Awards! Vote for Twenty Thousand Hertz in the Business and Television & Film categories. Follow the show on Twitter, Facebook, & Reddit. Subscribe to our Youtube channel here. Become a monthly contributor at 20k.org/donate. If you know what this week's mystery sound is, tell us at mystery.20k.org. Click here to leave us a voice message about your experiences with movie dialogue. Subscribe to Every Little Thing in Spotify. Get 10% off your first month of BetterHelp online therapy at betterhelp.com/20k. Visit zocdoc.com/20k to download the Zocdoc app and sign up for free. Get one month free of Headspace at headspace.com/20k. Find coupon codes on over 30,000 sites with Honey. Sign up for free at joinhoney.com/20k. Episode transcript, music, and credits can be found here: https://www.20k.org/episodes/liquidterror Learn more about your ad choices. Visit megaphone.fm/adchoices