The ‘Slender Man’, depicted, allegedly inspired the chilling attempted murder of a 12-year-old schoolgirl by her classmates.

The challenge quickly caught on, and soon, a character of unmistakeable terror was born. A fictional character, sure, but certainly one disturbing enough to put Stephen King and the Brothers Grimm out of business.

But a few years later, what started out as an innocent Photoshop challenge would soon become a real-life nightmare, after a pair of 12-year-old girls allegedly lured a classmate into the forest, where they held down and stabbed her 19 times.

When questioned, they claimed they did it in the name of this terrifying legend they’d read about online.

Now, despite this and other gruesome events it inspired, the eerie character is expected to rake in some serious profit in the form of a Hollywood movie.

IS IT APPROPRIATE TO MAKE A MOVIE?

The Hollywood Reporter has confirmed that a Slender Man movie is indeed on the way.

It remains unclear whether the horror flick will address the real-life incidents that took place, or simply revolve around the original legend.

The script will be written by David Birke (who wrote 13 Sins), and Mythology’s Bradley Fischer, William Sherak, and Zodiac scribe James Vanderbilt will reportedly produce it.

A separate documentary on the Slender Man killings, Beware the Slenderman, will premiere on HBO later this year.

Some might argue that such horrific cases as the Wisconsin girls would make a movie inappropriate.

A documentary on the two Wisconsin girls will be released later this year.Source:Supplied

Though at the same time, many fictional and semi-biographic horror events have been inspired by terrifying, jaw-dropping real-life events.

The Amityville Horror, for example, was based on a real-life family who moved into 112 Ocean Avenue, where a man had brutally murdered his family 13 months prior. In their new home, they claimed to see demonic animals and mysterious substances all over the house. The Conjuring had a similar backstory.

Psycho — one of the most famous thrillers of all time — was loosely based on convicted murderer Ed Gein, who killed women and fashioned human skin into accessories during the late 1950s.

And let’s not forget The Exorcist. Both the book and film were based around a group of Jesuit priests, who claimed to have exorcised a boy who was seemingly possessed by the devil.

Chilling stuff.

WHO IS THE ‘SLENDER MAN’?

The Slender Man was created on June 10, 2009, in an internet forum on SomethingAwful.com, which challenged users to edit ordinary photographs and make them appear paranormal.

Eric Knudsen (under the name “Victor Surge”) created the ‘Slender Man’ — an unnaturally long-limbed man in a black suit with no face, said to traumatise and abduct small children.

An artist's impression of the Slender Man. Credit: ImgurSource:Supplied

The man was edited into old photographs, and Knudsen added fake quotes to make them seem creepier and more realistic.

The creator added a quote to this depiction, which 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’.Source:Supplied

The concept somehow struck a chord with the creepy blank-faced figure showing up in short horror stories all over the internet.

Some stories describe him as a man who lived in the forest, but would venture out to playgrounds to prey on small children. He would vanish with them to mysterious, untraceable locations, or remove their organs and place them in bags around the forest.

In other stories, he would trap and psychologically torture his victims, slowly driving them into madness at their situation of being unable to cope. Other times, he would somehow compel his victims to murder each other.

The original posts exist to this day.

WHEN AN ONLINE MYTH TAKES A TERRIFYING TURN

The Slender Man gained global media attention after a series of horrific real-life attacks were attributed to the legend.

The most well-known is that of Morgan Geyser and Anissa Weier, a pair of 12-year-old girls from Wisconsin who in 2014 allegedly lured their classmate, Payton Leutner, into the woods for a game of hide-and-seek.

Morgan Geyser and Anissa Weier, both 12, at the time they allegedly stabbed their friend 19 times. Picture: Waukesha County Police DepartmentSource:Supplied

Once they were there, they stabbed her repeatedly with a knife. After leaving her with 19 wounds, the girls left her there to die, but miraculously, Payton managed to crawl out of the woods, where a cyclist discovered her lying in her own blood on the side of the road.

One of the wounds came within a millimetre of piercing a major artery near her heart.

The victim later told US media she’d “sensed something was wrong” in the forest, and tried to back away, but the girls had allegedly held her down.

Morgan Geyser’s notebooks were shown to the court, revealing eerie scribbles of the Slender Man and a list of supplies she believed she would need to carry out the attack.

A page in Geyser’s notebook depicting the Slender Man.Source:Supplied

Geyser’s drawings were incredibly eerie.Source:Supplied

A list of written supplies that would be ‘nessecary’ (sic) to kill the girls’ classmate.Source:Supplied

The court also saw the girl’s Barbie dolls, which appeared to have various stab wounds all over them.Source:Supplied

It’s been alleged the attack was carefully planned over five months.

There are conflicting reports as to what may have motivated such a horrific crime, but they all centre around the legend.

The girls reportedly claimed murdering the girl would bring them to the Slender Man, believing it would earn them a place in his “mansion in the woods”, where they would be under his protection. Police documents also allege the murder was partly to prove his existence.

Other reports suggest the girls did it out of fear. Geyser’s lawyer told a pre-trial hearing in Waukesha, Wisconsin, that the then 13-year-old believed her family would be killed “in three seconds” if she didn’t carry out the attack.

Eric Knudsen, the creator of the legend, gave a media statement in which he said: “I am deeply saddened by the tragedy in Wisconsin and my heart goes out to the families of those affected by this terrible act.” He added that he would not be giving interviews about it.

Last year, the girls were charged as adults with attempted first-degree intentional homicide.

In a separate incident in 2014, a 14-year-old allegedly set her house on fire while her mother and brother were sleeping inside.

After rescue workers searched for the girl, her mother allegedly received texts saying “Mom Im so sorry I dont know why I did it” and “Did any of u get hurt.”