Specifically what I'm talking about is "Slender-Man". He is only fictional but still, he is creepy as fuck.
Definition - "Slender Man is a mythical creature often depicted as being tall and thin, wearing a black suit with a white shirt and necktie, and having a blank face. He can stretch out or shorten his arms at will, and hides some kind of tentacle-like appendages on his back. He has inspired pictures, fictional stories (creepypastas) and videos."
He stalks children and as the story goes they are then reported as missing. He just has a eerie presence in my opinion.