Slenderman

Slenderman is a free entertaining horror game that focuses on a minimalistic approach. It involves no weapons or other fighting abilities. It's a pure frightened experience. Slenderman started as a project for 64Digits contest and has been released prior to Slender, the game created by "Something Awful" team.
The Slender Man is described as very tall and thin with unnaturally long arms, which it can extend to intimidate or capture prey. It has a white, featureless head and appears to be wearing a dark suit. The Slender Man is associated with the forest and has the ability to teleport.

The Slender Man was called "the first great myth of the web" by the BBC. The success of the Slender Man legend has been ascribed to the connective nature of the Internet. While nearly everyone involved understands that the Slender Man is not real, the Internet allows others to build on the established tropes, and thus lend an air of authenticity to the character. Victor Surge has commented that many people, despite understanding that the Slender Man was created on the Something Awful forums, still entertain the possibility that it might be real