I've been looking on SoundEffectsWiki for the name of this certain sound that always creeped me out as a kid. It sounds like a very detuned electric guitar with heavy feedback, and the sound first rises in pitch before a stop drop.
As a kid, I remember hearing it in more places than one. You can hear it used in The Hobbit (2003) at exactly 3:14:17 in this video.
Any help is appreciated! I'd love to know which sound library it comes from too.