Who is Slender Man: What you need to know

Two American teenage girls brutally stabbed a friend 19 times after they developed an unhealthy fascination with a fictional character known as 'The Slender Man'

The 911 call made by a cyclist who discovered a girl lying on the road after being attacked by her classmates in a disturbing tribute to the mythological internet character Slender Man has been released by police.

Two American girls have been charged with first degree attempted murder after they lured a friend into the woods before stabbing her 19 times. The girls plotted the assault after they developed a fascination with a horror figure known as 'The Slender Man'.

But what is 'The Slender Man'? A fictional Internet character, The Slender Man is known for his ghastly appearance, unnaturally long arms and torso, and always wears a dark suit. According to the myth, he hypnotises his victims, mostly children, and his followers must show their dedication by killing.

When and how did it originate? The Slender Man first appeared on Something Awful Forums in 2009 as part of a contest in which users altered seemingly normal images, adding horror elements using photoshop.

A user known as 'Victor Surge' posted two black and white photographs of children haunted by a paranormal creature described as The Slender Man.

The captions read:

We didn't want to go, we didn't want to kill them, but its persistent silence and outstretched arms horrified and comforted us at the same time…

1983, photographer unknown, presumed dead.

One of two recovered photographs from the Stirling City Library blaze. Notable for being taken the day which fourteen children vanished and for what is referred to as “The Slender Man”. Deformities cited as film defects by officials. Fire at library occurred one week later. Actual photograph confiscated as evidence.

1986, photographer: Mary Thomas, missing since June 13th, 1986.

Why is it so popular? The Slender Man is often featured in blogs and online forums dedicated to horror stories such as Creepypasta Wiki and Reddit's No Sleep. Fans of the character write and share horror stories about The Slender Man.

Why did the girls attack their friend? According to investigators, the girls had developed a fascination with the character and wanted to please him. One of the them told Wisconsin detectives they were trying to become "proxies" of Slender Man. The other allegedly said he appeared in her dreams.

What has the reaction been so far? Creepypasta Wiki, the online forum where the girls allegedly read stories about The Slender Man, issued a statement after the news broke condemning the attack. The site insisted the brutal attack is an "isolated" incident and does not represent the Creepypasta community as a whole.

"This wiki does not endorse or advocate for killing, worship, and otherwise replication of rituals of fictional works. There is a line of between fiction and reality, and it is up to you to realize where the line is. We are a literature site, not a satanic cult," it added.

What happens next? The girls, both 12, are due to appear in court on 11 June.