Slenderman

Based on the popular monster made in the Something Awful forums. Slenderman is also the basis of the popular youtube-based series Marble Hornets and a smattering of blogs. He appears randomly when exploring Limbo and may attack the player character. He is known for stalking and kidnapping children.

Appearance
Slenderman is slender, which goes without saying. However, his most striking feature is his lack of facial features. His spiffy suit and his occasional tenticles are of note as well.

Other Information
Slenderman was originally going to be a dateable character, however, he was given a different role shortly after.