Slender Man is a thin, unnaturally tall man with a featureless face in a black suit, but where did this nightmare of the net come from? The fictitious stalker was created by Eric Knudsen who said he was inspired by Stephen King, HP Lovecraft and William S Burroughs The Slender Man first appeared on June 10, 2009 on the online forum Something Awful as part of a Photoshop competition to "create paranormal images", but the Slender Man soon went viral across the internet.