I'M TERRIBLE WITH CREEPY STUFF but if you don't mind korean horror, check out Distant Sky? it's a web series about a boy waking up in complete darkness. turns out the entire city of seoul kinda just fell into a hole and now there's crazy people everywhere, TIGERS ROAMING AROUND FREELY, more crazies, soldiers who kill civilians.. it's so weird and suspenseful and most of the time i had no idea what was going on. beware for gore-y images, suicide, and attempted rape though. the art isn't all that pretty but i guess that adds to the atmosphere since there's hardly any light (they mostly use flashlight apps on phones) and the characters just look so beaten up after a while as they attempt to find a way outside the hole.

OH I JUST REMEMBERED SOMETHING JAPANESE I READ it's called School Ningyo and.. well, two girls try to hunt mermaids at their school in the middle of the night. it's been years since i read it but i thought it was pretty neat. :3c