Yay, another video game music thread! Honestly, I think games are scarier without music - the atmosphere of silence is far more terrifying - but a few my favourites include...
Mind of Frenzy and
Sound of Bell from the Corpse Party OST. For a game with an otherwise fairly whimsical soundtrack, suddenly being confronted by these is a bit jarring, to say the least...especially because things go down whenever they start playing.
Gaping Dragon from Dark Souls. Dark Souls pumps it up to eleven with the boss themes half the time, and Gaping Dragon is by no means hard, but the first time I fought him I freaked right out, and part of it was because of this in the background. It was a literal "HOLYCRAPRUNRUNRUNSHITSHITSHIT" moment. Very anticlimactic as he was quite easy to dodge and kill, but that first moment...oh yeah.
Dancer of the Boreal Valley in Dark Souls III had the same effect on me recently...but then, I killed the NPC as soon as I saw her, and I was at a very low soul level, so my attacks did very little. That was a "I shouldn't have done that..." moment. Plus, as far as Souls themes go, it's bloody creepy.
Regenerator from Resi 4 is always accompanied by a shivering monster, so this is scary by default. Literally cannot deal with this. Nope. Nothing doing. Nooooo.
This is a bit of a weird one, but I find
A Sacrifice from Final Fantasy VIII to be quite scary, too. Or at least creepy. When you first meet her, Sorceress Edea is depicted as some half-crazy omnipotent witch who holds demonic summoning rituals disguised as festivals, and can block bullets with her bare hands. This played in her...uh, quieter moments. It's pretty spooky, in my opinion.
...there are more. I'll do a part two somewhen.