Originally Posted by Chonson
György Ligeti's Requiem. (You've probably heard it in Kubrick's 2001).
Very little to grasp onto, it's probably the most reliably unsettling piece of music I've ever heard.
This is EXACTLY the song I had in mind when reading the thread title. Listing to that song in the middle of the night with headphones on makes my testicles want to shrivel up into my stomach!!
Penderecki is another master of dissonance. Kubrick used some of his works in the Shining and other films as well, I believe.