A 12-year-old girl was stabbed 19 times by two of her friends this weekend who say they were inspired by a mythical Internet creature known as Slender Man.
What follows is Mashable's explanation of this horrific case and the mystery surrounding the bizarre online avatar that allegedly drove the girls' motives.
What happened?
The girls, Morgan G. and Anissa W. of Waukesha, Wisconsin, lured the 12-year-old victim into the woods on Saturday for a game of hide-and-seek after a slumber party the previous night.
"Once there, one suspect held down the victim while the other suspect stabbed the victim 19 times in the arms, legs and torso," Waukesha Police Chief Russell Jack said. "Many of the stab wounds hit major organs, but incredibly and thankfully, the victim survived this brutal assault."
The victim was left to die and eventually crawled out of the woods where she was found, bleeding, by a cyclist. The suspects were found nearby and taken into custody. The victim, police say, is lucky to be alive. She is recovering in a Waukesha County-area hospital, where she is reported to be in stable condition.
The girls told police they did it for Slender Man.
Slender who?
Slender Man is being called everything from "an online horror meme" and "a paranormal figure" to a "fictional web site character," a "fictional demon-like creature" and a "character conceived on an Internet forum."
Slender Man's origin story starts with a "paranormal pictures" Photoshop contest held on the Something Awful web forum in June 2009, according to the meme-tracking website Know Your Meme. A user named Victor Surge is widely credited with its creation, posting black-and-white images -- with creepy captions -- that showed a tall, faceless creature stalking children.

From there, Slender Man spread to 4chan’s paranormal board, where users created a plethora of hand-drawn images of the creature, and eventually landed on Creepypasta, a site where amateur horror writers can submit stories and get instant feedback from fans of the genre.
The site's administrator has since issued this statement on the stabbing: "most people don't watch Hannibal and turn into serial killers."
"I don't believe that it's the fault of Slenderman or horror writing in general that this happened," the administrator wrote. "I remember reading scary stories and watching slasher movies when I was a child and young teenager and while they certainly gave me nightmares, they did not instill within me a desire to murder my friends."
It's hard to express it well in a twitter status, but the families involved in the Wisconsin incident have my empathy, thoughts and prayer.— creepypasta.com (@creepypastacom) June 3, 2014
Fans of Slender Man have created YouTube videos, long-form fiction, and an endless amount of fan art over the years. Slender Man has become a true amalgam of a horror figure that lives in the minds of millions of Internet horror fans, a boogeyman for a generation that grew up on the web.
Slender Man lives! #abandonedbuildings #graffiti pic.twitter.com/kSQWqHIN1f— S Sills (@WX_SSills) May 18, 2014
"There is not just one Internet site they were accessing to get this information. There are multiple websites of a similar nature that deal with the particular incident," Jack, the police chief, said.
The #slenderman. Terrifying pic.twitter.com/zjFiPXfzOZ— Greg Hill (@GregHillWAAF) June 3, 2014
What does Slender Man have to do with the attempted murder?
The girls told police that they committed the crime as a sacrifice to Slender Man, believing that if they killed their friend they would become one of his “proxies.” When asked why, the girls reportedly said they had to do it -- or “he” would kill their families.

The girls believed "Slender," as they affectionally called him, lived in a mansion in a nearby national park where they would retreat to after killing their friend to become one of the fictional character's proxies, a status only attained once a murder has been committed (according to at least one story the girls allegedly read).
When picked up by the police, one of the girls reportedly said, “It was weird that I didn’t feel remorse.” The other: “The bad part of me wanted her to die. The good part of me wanted her to live.”
What happens now?
The girls have been charged as adults for plotting to kill their friend, and are being held on $500,000 bond each. If convicted, they each face up to 65 years in prison. Defense lawyers are attempting to get the case moved to juvenile court, where the proceedings would occur in anonymity.

Jack says the incident should serve as a wake-up call for parents. "Parents are strongly encouraged to restrict and monitor their children's Internet usage," he said. "We must also remember that online is much more than just spending time on the computer, now smartphones and even video games are completely connected to the outside world. Parents, please talk to your kids about the dangers that exist online.”