Nightmarish music.

I've been really into types of music with extremely dark tones/sounds or otherwise 'nightmarish' atmosphere to it. Do any of you guys have recommendations?

Some examples, I suppose:

http://www.youtube.com/watch?v=oSMhqtAQK5o
http://www.youtube.com/watch?v=7-mYjpNsPPA
http://www.youtube.com/watch?v=drALbzXjHK4

anything by Nox Arcana

https://www.youtube.com/watch?v=1lvC8b1_2bI

http://www.youtube.com/watch?v=3vdRzfekf3s

Double post, but this is my favorite track by them.

https://www.youtube.com/watch?v=UwKUbPDWrs4

Try some stuff by Mastodon. It's about as close to that I can think of.

http://www.youtube.com/watch?v=UDcGO3zsyXI

http://www.youtube.com/watch?v=4OK1kDLj8MM

http://www.youtube.com/watch?v=mkR66Q-UdYA (takes a little bit to get going)

http://www.youtube.com/watch?v=WMYldrVZf0g

http://www.youtube.com/watch?v=F5nzwqj3utY

http://www.youtube.com/watch?v=ekbPoD4mbw0

http://www.youtube.com/watch?v=C6Il58Ln4cI

http://www.youtube.com/watch?v=awzNxCazXHQ

http://www.youtube.com/watch?v=fG7yHCbMQ40

http://www.youtube.com/watch?v=Qsox-MIKLkQ

http://www.youtube.com/watch?v=xpMNXEY_tio

http://www.youtube.com/watch?v=HS8J_Oky5cw

http://www.youtube.com/watch?v=Q7a_Zy7oBik

https://www.youtube.com/watch?v=li-adM-qOwI

https://www.youtube.com/watch?v=Z96I_LEGdGQ

https://www.youtube.com/watch?v=xYDG...ature=youtu.be

https://www.youtube.com/watch?v=LX-n_lJlJ68

https://www.youtube.com/watch?v=rsHIzhaNOYU

https://www.youtube.com/watch?v=btWYiCZSvUE

You might want to check this out. It excels in 'dark tones', but isn't as fast as your examples. In fact, it's pretty slow. Still worth a try I'd say.

http://www.youtube.com/watch?v=ECyfX1OR_nk

Cradle of Filth - Venus in Fear

Give this right here a try.

http://www.youtube.com/watch?v=Z1q3bWxB_EU

Try Drumcorps,Whourkr, and Godspeed you! Black Emperor.