Beware the Slenderman has been on my radar since the documentary got really good reviews out of SXSW. While the idea of a documentary about an internet boogeyman might not sound like affecting material the story it tells is of a very real tragedy.
The film tells the story of how two 12 year old got so enveloped in the myth that they lured a best friend out to woods and repeatedly stabbed her. It sounds like harrowing stuff, and it is finally making its way out out of HBO. There is no release date on it yet, besides a 'coming soon' card for right now though.
Here is the first trailer for it though, and while I think it is tonally a little weird, it does set the story up.
Take a look: