Hitman and Slender man resemblance  

I dunno if it's true but i think that whoever made slenderman must of got a few features from Agent 47 from the Hitman series. Hitman and Slender man both use stealth and have similar features in appearance including black suit, white striped dress shirt, completely bald head and pale skin; the only difference is that Agent 47 has a red tie, black leather gloves and has a facial appearance while Slender man has a black tie and no facial appearance.