Morgan Geyser

On March 31, 2019, another movie inspired by the Slender Man stabbing titled Mercy Black, starring Daniela Pineda, was released to Netflix with no prior announcement. Directed by Owen Egerton and produced primarily by Blumhouse Productions, it tells the story of two girls with pre-schizophrenia who attempt to murder their friend, believing that a spirit named Mercy Black will offer them a gift in return. Later, the protagonist is released from psychiatric care, and has to deal with the realistic and paranormal consequences of her actions.

On October 24, 2019, more than five years after the stabbing, Leutner, then 17, spoke publicly about her experience for the first time. She spoke of her scars, saying, "I don't think much of them. They will probably go away and fade eventually." She told the interviewers that she met her attackers in fourth grade. When asked what she would say if she ever saw Geyser again, Leutner added that she would "thank" her because the attack inspired her to pursue a career in medicine.

In 2018, a Wisconsin judge sentenced Geyser to 40 years under mental health facility's supervision. While Geyser will periodically have the opportunity to petition for her release from a mental health facility in the future, she will remain under institutional care for the duration of the sentence. During her trial, Geyser had been committed to the Winnebago Mental Health Institute and was the youngest patient there.

The Criminal Minds episode "The Tall Man" (Episode 14.05, airdate October 31, 2018) was also inspired by this story.

On October 14, 2018, a movie inspired by the Slender Man stabbing called Terror in the Woods aired on Lifetime. The film stars Ella West Jerrier, Sophia Grace McCarthy, Skylar Morgan Jones, Angela Kinsey, Drew Powell, and Carrie Hood. Christina Ricci serves as the executive producer of the film.

In 2017, Weier pleaded guilty to being a party to attempted second-degree homicide. A jury then found her "not guilty by mental disease or defect." Geyser accepted a plea offer under which she would not go to trial and would be evaluated by psychiatrists to determine how long she should be placed in a mental hospital. She later pleaded guilty but was found not guilty by reason of mental disease or defect, and was diagnosed with schizophrenia, from which her father also suffers.

A documentary film on the incident called Beware the Slenderman was released by HBO Films in March 2016, and was broadcast on HBO on January 23, 2017.

On May 31, 2014, in Waukesha, Wisconsin, two 12-year-old girls lured their best friend into the woods and stabbed her nineteen times in an attempt to prove the fictional character Slender Man was in fact real. The victim crawled to a road where she was found. She recovered after six days in the hospital. The perpetrators were found not guilty by mental disease or defect. By February 2018, they both were sentenced to long periods in mental health institutions.

Weier and Geyser initially planned to attack Leutner on May 30, 2014. They planned to tape the victim's mouth shut, stab her in the neck, and flee. They did not carry out that attack; Weier and Geyser were believed to be "too tired" or "too groggy." A second plan called for attacking Leutner in a bathroom at a local park, choosing the location for the fact that the bathroom had drains for Leutner's blood.

The actual attack took place in a nearby forest (David's Park) during a game of hide-and-seek on May 31, 2014. Leutner was pinned down and stabbed 19 times in the arms, legs, and torso with a kitchen knife with a five-inch-long (13 cm) blade. Two wounds were to major organs, one missed a major artery of her heart by less than a millimeter, and another went through her diaphragm, cutting into her liver and stomach. Weier told the victim to lay down because the blood will come out slower. Weier and Geyser then told Leutner they would get help for her, but instead simply left. Leutner dragged herself to a nearby road where she was found by a cyclist.

Leutner left the hospital seven days after the attack. She returned to school in September 2014.

On August 12, Wisconsin Governor Scott Walker issued a proclamation declaring Wednesday, August 13, 2014, "Purple Hearts for Healing Day" and encouraged the people of Wisconsin to wear purple on that day to honor the victim of the stabbing. He also praised the "strength and determination" exhibited by the victim during her recovery.

The victim, Payton Leutner, and the perpetrators, Anissa Weier and Morgan Geyser, were all 12 years old at the time of the stabbing, and were classmates enrolled in the same school. The school's principal later confirmed that neither Weier nor Geyser had any prior disciplinary issues. They had been at a sleepover together the night before the stabbing. The attackers had discovered Slender Man on the Creepypasta Wiki. They later said they had believed Slender Man to be real, and had wanted to demonstrate their loyalty to him so they could become his "proxies," prove his existence, and prevent him from harming their families. They believed that the only way to do this would be to kill someone, after which they would become servants of the Slender Man and live in his mansion, which they thought was located in Chequamegon–Nicolet National Forest. Geyser explained during police interviews that she had seen and heard hallucinations of ghosts since the age of three, and was certain that Slenderman demanded she kill her best friend to save the lives of her own family.

Members of the creepypasta community held a 24-hour live stream on YouTube June 13–14, 2014, to raise money for the stabbing victim. Joe Jozwowski, an administrator on a creepypasta website, said the purpose of the stream was to show that members of the community cared for the victim and did not condone real-world violence because they enjoyed fiction that contains violence.

Slender Man is a fictional entity created on the Something Awful online forums for a 2009 Photoshop paranormal image contest. The Slender Man mythos was later expanded by a number of other people who created fan fiction and additional artistic depictions of the entity.