Slender Man is an internet meme and urban legend, first gaining stardom in the Something Awful forums, and branching out across the web as a figure that has established his own myths.
He is popularly viewed as some sort of malevolent demon that abducts and psychologically traumatizes people, particularly children. Though what he does with them is unknown, it is speculated he kills them or takes them to another dimension. In some versions of the legend, he will impale captured victims on tree branches and save them for later skinning and consumption.
It is widely considered that his "faceless pale man in a suit" persona is really a smaller form and that his true form is beyond comprehension for mortals. It is also thought that he may have a long-term (possibly cataclysmic) goal in mind, but this is specifically uncertain.
He is widely recognized as a sort of pop culture icon and also a very controversial figure, and is a prime example of a Creepypasta villain at its best, being featured in many fictional stories around the web. Slender Man's motivations vary depending on version, but the original has him as a misanthropic predator that despises humanity and takes great pleasure in sadistically torturing them before devouring them; when he is not feeding, he simply likes to torture and kill. Some believe that he is real and sightings have been reported from diverse locations.
Slender Man was created by Eric Knudsen. He was also inspired by Stephen King's short stories, HP Lovecraft and William S Burroughs.