We had no idea what Irene Taylor Brodsky’s Beware the Slenderman was when it was announced to have its World Premiere at the upcoming SXSW Film Festival in Austin, Texas.

Based on the iconic character that started on the Creepy Pasta Something Awful forums years ago, “In this horrifyingly modern fairytale lurks an online Boogeyman and two 12-year-old girls who would kill for him. The entrance to the internet quickly leads to its darkest basement. How responsible are our children for what they find there?”

Indiewire has premiered the film’s official one-sheet that reveals it’s actually a documentary from HBO Films, who is behind some fantastic stuff like last year’s mind-blowing “The Jinx: The Life and Deaths of Robert Durst”.