The Slenderman

A being often presumed to be a Tulpa.

Information Limited
Very little is known about the Slenderman. All that is really clear is that it gives off a rare form of radiation, has been known to mentally control other beings into doing its bidding as Proxies, and that nothing seems to hurt it. Recent data suggests that it may not be a mere Tulpa, but an even more enigmatic being, and even more deadly. Avoid at all costs.