All horror movies rely in some degree or another in creating a perfectly harmonious reality and then viciously and repeatedly disrupting it. That's why they open on scenes of family joy, of car rides between friends, and with lots of laughter. They've got to show you happiness before it's taken away.
One of the best and easiest ways to build audience dread, which is the more effective tactic than jump scares, is through music. That's not a major insight. But often finding the right music, inharmonious and somewhat strange can present a technical challenge. So many horror composers turn to the waterphone.
That's included movies like Poltergeist, Let the Right One In, Aliens, and even The Matrix. Here's a demonstration, it's truly a strange sound.
The Waterphone was invented by Richard Waters and based on a Tibetan Water Drum and several other non-Western instruments. It's gone through several iterations, but basically is produced only by him and his appointed successor.
Read more about the story behind its creation here.