Nothing too hard. I just found Liszt's "Nuages Gris" and I liked it. Chopin's Prelude Op 28 No 2 is also quite disturbing.
You hink that's spooky? Try listening to these!
Scriabian sonatas 6-10, try listening to these first before everything I mention.
Ravel's Scarbo
Prokofiev's Diabolique Suggestions
Anything from Schoenberg or atonal
Or actually you can listen to any or Scriabians late works, but I think his Sonatas are the creepiest. He was scared to perform his 6th one on public. He would play a few measures and recoil back in fear! I think that one was named the insect sonata? So then he composed his 7th one "White Mass" to exorcise the 6th one, but that one is pretty scary as well. And then there's the 9th "Black Mass" sonata! That one is soo creepy!!! I imagine the beginning to sound like people saying their prayers backwards because that's what they do at a black mass, and then it turns into this really weird orgy and people drinking each others blood and pee, slitting each others throats, insects flying everywhere feeding on the dead, it's sooooooo creepy and disgusting! Those I think are the scariest, but the 8th and 10th are pretty scary as well. Oh and you should listen to the 5th one! It's more romantic than scary, but it's like literally about sex and drugs. The beginning and the end projects a person getting REALLY high!!! But yeah, if you listen to the 9th or 6th in the dark, you'll be like really creeped out.
And then there's Ravel's Scarbo! It was supposed to be the most difficult work in all repertoire, but now we have Petrouchka, Scriabin's 7th, 8th, and 5th sonata, etc. It's based off of a poem about a little monster running around in the night trolling people. It's pretty scary, you're like in your bed, and this monster is running around your room, so you hear something, but then you look, and nothing is there! Or you see a shadow, it gets bigger and bigger, but then it disappears! this is supposed to be a nightmare to listen to, and play considering it's difficulty.
And finally there's Prokofiev's Diabolique Suggestions! I don't think it's as creepy as above, but I'm pretty sure this has been used in horror movies. You're probably really familiar with this once you hear it.
Oh wow never mind! I didn't know it couldn't be too difficult! Sorry. But you should listen to them anyways!