In 2014, two teenage girls in Wisconsin named Morgan Geyser and Anissa Weier were accused of stabbing their friend Payton Leutner 19 times. Those girls claimed that they did it to summon a fictional character called Slenderman. Slenderman is a video game character turned internet meme, and his power to inspire violence is disturbingly high.
This bizarre situation obviously intrigued director Irene Taylor Brodsky, who decided to investigate the story in the upcoming documentary "Beware The Slenderman." The creepy documentary premiered at SXSW, and now it's coming to HBO.
Payton Leutner survived the attack, and Geyser and Weier are currently behind bars, but the Slenderman still remains at large.
Check out the trailer for "Beware The Slenderman" above, and a clip from ABC about this creepy myth below.