First appearing in 2009, Slender Man (also spelled Slenderman) is a supernatural character created by Erik Knudsen. This design was part of a photoshop contest for Reddit, and the creature has since spawned many stories, videos games, movies, and even real-life attempted murder.

He is shown as an unnaturally tall and thin figure with a white head, wearing a black suit and lacking a face. He is also occasionally depicted with multiple long tentacles.

He is not directly aggressive at first, and takes a rather slow approach when interested in a victim. He often stalks them for multiple years before ever making actual contact, using this as a tactic to drive fear and paranoia. There are multiple theories on how Slenderman attacks, with some of the most common ideas being stabbing victims to a tree and waiting for them to bleed out, as well as strangling the victims with his tentacles. Others believe that Slenderman wants others to carry out his killings for him.

Slender Man was even the inspiration for an attempted murder case that occured in Wisonsin in 2014. Two 12 year old girls, Anissa Weier and Morgan Geyser lured their friend, another 12 year old girl, into the woods and stabbed her repeatedly, totalling 19 times before leaving her in the woods to die as an attempt to appease Slender Man. Miraculously, though, the victim survived and the two girls are currently in mental instituions.