Since it is halloween I have animes that can get you in the spooky mood 

1.Tokoy Goul (pain and simple)

2.Black Bulter (Demons soooo ya)

3.Death Note (May the title say no more)

4.Parasyte (Need I say more)

5.This one is not a anime but it scare non the less Doki Doki Literature Club(well give you nightmares for days)

JUST MONIKA >:D