>>369431There aren't really any true horror anime, you get thrillers at best.
>Perfect Blue>Paranoia Agent>Paprika>Mononoke>Shiki (kinda hard recommending this one given that the first half is pretty uneventful, but I think it's worth it for the other half)>Parasyte (from what I know, some people don't like this adaptation)>Aoi Bungaku (only the first story, maybe the folk tale one too)>Vampire Hunter>Hellsing>Jigoku Shoujo (I used to watch this one back when I was a kid, it was spooky back then, now probably not so much) 