Just as a note, I really don't remember what the recommended age for the manga was so if this post should go in the 18+ area, I'm really sorry and I didn't know >_<
Anyway, I read this recently released horror manga, and as far as I know there has been only 1 chapter released. It's about this group of teenagers how go to this old mansion in this old amusement park to search for this girl who had disappeared a few years ago. They get in and this mysterious fog makes them all pass out and when they wake up they are trapped in the room they were in, but they have these collars with a spike on their necks. Then this person with an owl's face tells them that they have to travel in pairs and never walk backwards while they search for him (the owl faced person). I can't remember the name for the life of me!