You are watching a late night horror movie and suddenly the screen turns dark and the ax wielding zombie sneaks up behind our hero and does his best to take our star out of the movie for good. Chances are, as our evil zombie approaches our hero, you suddenly get a dose of those crazy horror movie sounds.

Ever wonder how the movie producers make those creepy sounds? It's in instrument called a waterphone! Check out the instrument in action as it makes a smooth, eerie sound that's regularly featured on movie soundtracks. Here's how it works: