WAUKESHA, Wis., Nov. 11 (UPI) -- HBO tackles the Slenderman stabbing and the ensuing trial in the first trailer for their latest documentary, Beware the Slenderman.
The clip released Wednesday, brings the fictional horror character created on the internet to life while also featuring footage from the still ongoing trail of Morgan Geyser and Anissa Weier who are charged with stabbing a fellow classmate 19 times in order to appease Slenderman.
The documentary also features new interviews from experts discussing the effect the character had on the pre-teens and how fictional stories could have driven them to commit the vicious attack.
"They don't know how to differentiate between fantasy and reality," notes one featured commentator.
Slenderman also labeled Slender Man, was created in 2009 as part of a Photoshop competition on Something Awful, an internet forum.
The character who appears as a tall, faceless man wearing a suit, then went viral with various fanart and fictional stories about Slenderman being released online.
Lawyers for Geyser and Weier who were 12 at the time of the stabbing, have argued that the girls acted out of fear that Slenderman would kill their families if they did not kill their friend.
Both girls have been diagnosed with mental illness and will be tried as adults.
Beware the Slenderman is set to air on HBO starting Jan. 23, 2017.