The creepy meme that inspired two-12-year-old girls to attempt to kill their classmate has been made into a documentary: Beware the Slenderman.

In 2014, Anissa Weier and Morgan Geyser lured their 11-year-old schoolmate Payton Leutner out to the woods and stabbed her. She miraculously survived the attack that saw her stabbed 19 times, as she crawled to a nearby bike path and was discovered by a cyclist. Geyser was diagnosed with early onset schizophrenia, but after legal battles, July 2016 saw the Wisconsin Appeals Court ruled that the now 14-year-old girls would be trialled as adults, a trial that’s still playing out for first-degree attempted homicide.

The girls discovered Slenderman – who they called ‘Slendy’ – on creepypasta.wikia.com, an online archive for horror stories. One of the girls claimed Slenderman – a tall, faceless ghoul – was watching her, and that they planned the murder because otherwise “he would kill our family”. The pair believed they could run away to his mansion in the forest after they’d completed the act.

Beware the Slenderman uses footage from interviews by investigators with Weier and Geyser, people close to the girls and experts that unpack the power of fictional internet creatures.

The director of the documentary, Taylor Brodsky, told Buzzfeed: “The narrative does not revolve around guilt or innocence, but instead the court's deliberation whether the girls should be tried as adults or children. Above all, it is the anguish and astonishing honesty of the girls' parents that anchors the film's narrative to its tragic core.”

Originally created by Eric Knudsen for a Photoshop contest, the meme is also reportedly getting its own horror film, according to The Hollywood Reporter, which was announced back in May.