Morgan and Anissa stabbed their friend 'because of Slender Man'. This is their lives now.

Black suit. Blank face. Long, slender arms.

Since 2009, The Slender Man has slowly inched his way into every corner of the internet.

The terrifyingly tall supernatural character first originated as an internet meme who scared, abducted and traumatised children,

But in 2014, Slender Man became horrifyingly real.

On May 31 2014, the morning after a sleepover party, Morgan Geyser, Anissa Weier and Payton Leutner headed to the local park to play.

While walking to the park, Payton was walking ahead when Morgan and Anissa dropped behind. It was at this moment that Morgan revealed to Anissa what she was hiding under her jacket: a kitchen knife with a black handle.

Once they arrived at the park, Anissa suggested the friends play hide-and-seek, with Morgan counting.

It was then that Anissa attempted to tackle Payton.

After failing to hold Payton down, things quickly escalated as Morgan brought out the knife.

Watch the trailer for Slender Man Stabbing: The Untold Story here. Post continues below…

“I’m not going to until you tell me to,” Morgan whispered to Anissa.

“Go ballistic, go crazy,” Anissa responded.

Morgan stabbed Payton 19 times, missing a major artery near her heart by just the width of a human hair.

“One suspect held down the victim while the other suspect stabbed the victim 19 times in the arms, legs and torso,” police said at the time. “Many of the stab wounds hit major organs, but incredibly and thankfully, the victim survived this brutal assault.”

Morgan and Anissa washed themselves of Payton’s blood in the Walmart bathrooms. They then set out for the woods.

Payton was left to bleed out in a ditch outside the park. Despite barely being able to speak, the then-12-year-old crawled to a nearby path where she was found by a passing cyclist.

Miraculously, she managed to survive the attack.

Morgan and Anissa, who were also 12 years old at the time of the attack, told police that they attempted to kill Payton to protect their families from Slender Man.

They said they believed that once the murder was carried out, they would prove their loyalty to Slender Man and serve as his servants in his mansion, which they believed was located in the Nicolet National Forest.

Now, five years on, all three girls have very different lives.

In August 2017, Anissa pleaded guilty to attempted second-degree homicide and in December 2017, she was sentenced to 25 years in a psychiatric hospital after being found to be mentally ill at the time of the attack. She will remain there until she is 37 years old.

Morgan Geyser also pleaded guilty to attempted first-degree murder. She was sentenced to spend 40 years in a mental health unit.

Since the stabbing, both girls have been psychologically examined.

Anissa was diagnosed with depression, delusional disorder, and schizotypy, which is defined as a "diminished ability to determine what is real and what is not real."

Morgan was diagnosed with schizophrenia as well as defiant disorder.

According to a statement from Anissa's father, Anissa has taken on a 'mother-like' role within the facility where she is being held.

"She knows how things function there," he said. "She helps other kids with the day-to-day routine."

Little is known about Morgan within custody. However, it was revealed last month that Morgan is appealing her sentence.

For victim Payton Leutner, the lasting effects of the horrific crime will affect her for years to come.

In a victim impact statement shared to the court, Payton's mother shared that Payton initially struggled to get to sleep alone after the attack.

"When she did finally move back into her bedroom she refused to unlock the windows or open the curtains. She slept with scissors under her pillow," the statement read. "She couldn’t sleep unless I was in the room next to her and could respond to three knocks on her wall with three knocks on mine signifying 'I love you, you’re safe, and I’m here'."

The young girl has also been left with over 20 scars that stretch from below her neck to below her belly button.

"We are all still trying to figure out what it means to live in the 'new normal' that we have been forced to endure. We didn’t choose this life, it was thrust upon us unwillingly and we have had no choice but to stand up and deal with it in the best way we knew how."

New documentary Slender Man Stabbing: The Untold Story will delve deeper into the case, from the day of the arrest to the sentencing of both girls and question whether children should be tried as adults.

Slender Man Stabbing: The Untold Story airs tonight at 9.30pm on Channel Nine.