How Stephen King Inspired Slender Man, the Spooky Figure That Sparked Terror — and a Sixth Grader Stabbing

Slender Man is a suspected horrifying supernatural internet force who arrived on the scene in 2009. He grabbed the attention of viewers right away — too tall, too slim, faceless, but wearing a suit. His enormous arms reached out like spindly wings, seeming to grow to whatever length was necessary to steal children.

He is clearly almost human, half specter and half man. In some fictional works, his name is shortened to Slenderman.

Eric Knudson, who went by the handle “Victor Surge,” submitted a haunting black-and-white photograph of a group of children with a tall, slim figure in the background, his enormous arms outstretched as if to embrace them. It looked real enough, with a child bathed in sunlight in the foreground, drawing the eye to a group of children and a tall, dark figure in the background shadows.

The ghostly image hit a nerve, and its legend would grow to incredible proportions on the web over the next decade.

Culminating with near-murder.

Knudson created the idea of Slender Man with the help of his knowledge of horror fiction and true crime.

He was an avid reader of the great horror writers. He cited his inspirations as Stephen King’s “The Mist,” which contributed to Slender Man’s ethereal, ghostly presence. He said he was also influenced by shadow people, including and the legendary Mothman of “The Mothman Prophecies.” From real-life, Knudson pointed to the Mad Gasser of Mattoon, who seemed to disappear like the gasses he used to randomly attack people in the 1940s.

Knudson has tried to describe exactly what inspired him, saying he wanted to “formulate something whose motivations can barely be comprehended, and [a creature who caused] unease and terror in a general population,” according to Vanity Fair.

The Slender Man creator commented that his biggest influences were popular horror and fantasy writers King, William S. Burroughs and H.P. Lovecraft.

Knudson’s original post was a black and white photograph of a young child climbing up the ladder of a playground slide on a sunny day, with a silhouette of a group of children behind her, and in their midst a tall, slim figure with arms like branches, according to Heavy.com.

The caption read:

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.

But what makes Slender Man special is how he has lived on in the imagination of so many people. Other forum users, followed by internet users from around the world, built up the lore and backstory of Slender Man, adding creepy details to push him from a sketch into a fully realized character.

He became a staple on Creepypasta, where horror stories grew into larger-than-life urban legends.

Slender Man’s creator was stunned when his original images and captions went viral and, later, saddened when his boogeyman inspired an actual crime.

Slender Man isn’t one fixed image. He takes on characteristics that differ depending on whatever story is being told about him. His look is always slim, with unnaturally long arms.

He always appears in the guise of something near-human, however. The face can change, sometimes blank and white, sometimes a kaleidoscope of faces that make it impossible to identify a single person or feature.

It’s hard to recognize this phantom as anyone in particular, but his universal human-like features intertwine to cross-cultural boundaries. He is human enough to walk on two legs, use his spindly arms, and wear a suit. He could be a deformed man, exaggerated in his features and this lent credence to the idea he could be real.

Teenagers were known to spread legends that if you look too closely into Slender Man, your interest or obsession will cause him to come after you. What happens to his victims is never specified. They disappear into the mists, as ghostly as their captor, to some grim fate.

His visage has inspired art, video games and homemade videos that can still be found all over the internet. He has been called a “pure product of the internet,” but tragically, his fictional horror spilled over into real life in 2014 in a suburb of Milwaukee, Wisconsin.

In 2017, an HBO documentary was released chronicling a real crime inspired by the Slender Man legend. “Beware the Slenderman” told the story of a 2014 attempted murder in which die-hard teen fans of Slender Man decided to take decisive action so they could become his legitimate followers and go live with him.

Two 12-year-old 6th graders in Waukesha, Wisconsin, found Slender Man in the usual place — on the Creepypasta Wiki, which contains a trove of horror stories meant to be as hair-raising as possible. The girls hatched a plan, once they realized that by carrying out the bidding of Slender Man, they might have an opportunity to visit his mansion in the nearby Wisconsin woods.

The girls carefully crafted how they would murder their intended target, a 12-year-old friend and classmate at Horning Middle School named Payton Leutner. Morgan Geyser and Anissa Weier were celebrating Geyser’s birthday with a sleepover. Geyser’s parents allowed her to have one other friend over, and the two chose Leutner.

On May 30, 2014, Geyser and Weier prepped to carry out their plan that night. After school, they went to Weier’s house to collect supplies — water bottles, granola bars and pictures of her parents and siblings. The photos were important, as Weier wanted to remember what her family looked like once she began her new life in Slender Man’s mansion.

Weier placed the last item in her backpack, a knife with a five-inch blade.

Both girls would later admit they believed Slender Man was real, and his home in a forest was where they would escape after they’d sacrificed their friend to who they called “the leader” of Creepypasta, according to The Milwaukee Journal-Sentinel. They called themselves, after what they’d read online, Slender Man’s “proxies.”

After leaving Weier’s house, the two made their way to Geyser’s house to begin birthday celebrations. Geyser’s dad drove them to pick up Leutner, and all three were deposited at Skateland. A little after 9 p.m., Geyser’s dad collected them. At 9:30 p.m., the three pre-teens went to sleep.

Leutner later said it was odd because Geyser usually liked to stay up late during a sleepover.

Leutner hatched the idea, telling Weier that by carrying out the murder both would become official Slender Man proxies. Weier claimed she went along, hoping the act would finally prove to skeptics that Slender Man was real.

But roller skating, followed by getting frozen yogurt, pushed back the schedule. Originally, the two girls decided to wake up at 2 a.m. and tie up Leutner, put duct tape over her mouth, then stab her and pull the covers over her head. They figured they could make a run for it till they reached the Slender Man’s castle in the north woods.

They settled instead for killing Leutner the next day in broad daylight. Weier pointed out she knew a good place, in nearby David’s Park. After getting permission from Geyser’s mom, the three girls took off for a Saturday morning on their own.

When they cornered Leutner in one of the playground bathrooms, Weier gave Geyser the knife, but she was too freaked out to use it.

To calm her down, Weier suggested all three take a walk in the woods. During a game of hide and seek, Weier tried ordering Leutner to lie face down in the dirt, but she wouldn’t go along with it, according to The Milwaukee Journal-Sentinel.

The two girls tried pushing Leutner down, but neither could go through with the stabbing. Finally, Geyser told Weier, I’ll do it once you tell me to. Weier reportedly told her to ‘go ballistic, go crazy,’ and Geyser began stabbing.

When finished, Leutner had 19 stab wounds. She was screaming and tried to stumble away, while Geyser and Weier kept trying to get her to lie down and be quiet. She ended up in the twigs and leaves of the woods next to the park.=

Afterward, Geyser placed the knife — wiped clean on her jacket — back into her bag.

Leutner was found by a passing bicyclist, who spotted a girl lying on the sidewalk near the park, bleeding from the torso, arms and legs. He called authorities, and an ambulance rushed her to the nearest hospital.

The two friends were located a few hours later, walking along I-94 with their backpacks. Both were arrested that day.

When the truth came out, adults finally came to understand the popularity of Slender Man and the power of the internet. The girls told police they knew Slender Man could read their minds and teleport. They were convinced he watched them.

Leutner was fighting for her life and her condition was grave.

Weier and Geyser were tried as adults. They expressed little remorse. They told police all about Slender Man, in an attempt to explain the logic of their actions. The charges were attempted, premeditated homicide. Payton would pull through after months of recovery.

In 2017, Weier pled guilty and was sentenced to 25 years in Winnebago Mental Health Institute, according to The New York Times. She was granted conditional supervised release in 2021 and allowed to live with her father.

Geyser was sentenced in 2019 to 40 years in a psychiatric facility. In May 2023, Geyser submitted a petition to the court to also be released from custody. Three months later, in August 2023, Geyser withdrew the petition. Her attorney, Anthony Cotton, however, told WTMJ-TV in a statement that his client "continues to make substantial progress in treatment and should be ready for release next year we expect."

On July 1, 2021, Weier, 19, was released from custody after serving just a few years of her sentence. Her release isn’t official —a hearing in September will determine if she’s given back her freedom, according to National Public Radio.

On Oct. 24, 2019, Leutner spoke publicly for the first time about her experience.

She told ABC News “20/20” that she’d considered Geyser her best friend prior to the attack. But things changed between 5th and 6th grade when Geyser became obsessed with the Slender Man legend and made a new friend, Weier.

Leutner never liked Weier, describing her as “cruel,” but became friends with her because “Morgan really loved her as a friend.”

Leutner described how she found the strength to stand up and get herself out of the woods after the stabbing, so someone might rescue her. It took months for her to recover, and doctors told her that the knife missed an artery by a millimeter.

She has shown remarkable empathy toward her attackers. She told interviewers, “Morgan is schizophrenic…it was not her fault.”

The only known Slender Man victim told “20/20” she planned to attend college with a goal of going into medicine. She says her career choice was inspired not by Slender Man but by surviving a trauma that taught her how strong she really is.

What led to the demise and death of Slender Man? Perhaps the monster ran his course as the boogeyman of a specific generation. What scared Millenials might not inspire fear in Gen Z. Fans and followers grew up, moving on to dealing with real-life worries instead of imaginary fears.

Or maybe it was the horror that took place in Wisconsin that ended many obsessions with the myth.

Over nearly a decade, Slender Man had a good run, inspiring Enderman in Minecraft and getting his own movie. He’ll come back in some other form one day, like all great legends do, and haunt another generation of kids and teens who won’t know where he came from.