When two 12-year-old girls allegedly stabbed their friend 19 times in the name of an Internet folk-tale figure, it raised questions about the origin and mythology of the character.

As can be best discerned, here is the background on Slender Man.

Slender Man's Origin

Slender Man is largely attributed to a photograph submitted to the Something Awful forum in June 2009 by "Victor Surge," a handle used by Eric Knudsen.

Knudsen's Photoshopped black-and-white image shows a tall, thin, ghostlike figure with tentacle arms reaching out to a group of children on a playground. He also included snippets of text, creating folklore for others to expand upon.

"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," Knudsen's post read.

Slender Man's Development

Slender Man quickly went viral, encouraging additional fan art and online fiction. The figure became a favorite on various creepypasta sites (named for cut and paste functionality), which feature horror stories.

Creepypasta.com released a statement about the stabbing Monday, expressing condolences to the victim's family, urging those with mental-health problems to seek help and clarifying the site's mission.

"I think it's important that people are able to see that Creepypasta isn't actually a group of murder-promoting serial killer fetishists or a Slender Man cult in the hopes that, for once, people will pay attention to the actual issues surrounding this tragedy ... rather than finding something else to blame so that they can bury their heads about the larger societal issues that these ever-increasing occurrences imply," the statement read.

Slender Man and Mind Control

One of Slender Man's primary characteristics in the mythology about him is his ability to control his subjects via telepathy.

"It seems there is a mental link with the subject, always allowing Slender Man to follow. Subjects who've been in contact with him have shown symptoms of paranoia, delusions and complete personality
changes," according to the YouTube video The Slender Man Is Real!!!.

One of the girls allegedly claimed to see Slender Man in her dreams, according to the criminal complaint. She said he watches her and can read her mind and teleport.

Slender Man's Proxies

The girls accused of stabbing their friend said they did it in order to become "proxies" of Slender Man, according to prosecutors. One Slender Man site explains: "Proxies are entities or people who are under the influence or control of Slender Man … and act based on its wants/needs – hence, Proxies serve as an in-between – a proxy – for Slender Man."