While Beware the Slenderman isn't an easy watch-and will undoubtedly inspire anxiety and panic in some viewers, particularly parents-it's a worthy one that helps make sense of a senseless crime.

Harnessing the simplicity and reach of the Internet is an appropriate technique for this doc, because it's about just that. But using Skype is also a genius tip for any doc maker on a budget. Which is every doc maker.

What emerges is a portrait of the internet as the birthplace of contemporary folklore -- a virtual campfire in which disparate users come together to channel, and distill, their fears, anxieties, and dreams into fanciful tales, la the Brothers Grimm.

Beware the Slenderman is a deeply sad and ultimately tragic story that will make you consider how our legal, medical and mental health systems are actually working. You won't sleep well, but not for supernatural reasons.