I’ve always been a fan of being scared. Even when I was a little kid and my elementary school had a book fair, I didn’t buy Encyclopedia Brown; I picked up the Dynamite Book of Ghosts and Haunted Houses — because even at that age, getting freaked out of my mind was cathartic in a way I couldn’t really express. That developed over the years (Mr. King and Mr. Barker, please meet my new friend Mr. Lovecraft), and about 10 years ago I discovered the haunted house scene. You know what I’m talking about; the kind of place where you pay $60 to have people with chainsaws chase you into tiny rooms filled with fake body parts. But you can only see so many Leatherfaces before it starts getting goofy, which is how the New York-based production Blackout got on my radar.

If you’re not familiar with Blackout, it’s something that its creators call "immersive theater." People sign a waiver absolving Blackout from any responsibility should anything happen to them, and walk alone through a darkened space where… things happen. Violent things. Sexual things. Degrading things. Things that take it far from the realm of "Oh look, there’s a guy with a Freddy Krueger glove," and into the territory of "This place has a safeword policy and if you suffer from PTSD you probably shouldn’t go." But despite (or perhaps because of) its nefarious reputation, I haven’t experienced Blackout myself, so when I saw that a new documentary called The Blackout Experiments was going to be at Sundance, it seemed like the perfect opportunity to find out if this experience was something I was going to be interested in.

Oh boy.

Directed and edited by Rich Fox, Experiments follows a handful of different individuals in Los Angeles as they try Blackout and either swear it off forever, or keep going back again… and again… and again. Fox does capture some footage of what happens inside the mysterious attraction, and he uses plenty of horror movie gimmicks to set the tone. Static randomly glitches through video footage, and disturbing sound design punctuates every scene. But at first, the footage of Blackout itself doesn’t seem that scary in the conventional sense. There’s brief glimpses as the film’s primary subject, a man named Russell Eaton, is literally grabbed off the street and dragged into his first Blackout experience — afterwards he’s dumped onto the sidewalks of downtown Los Angeles, only partially clothed — but the moments seem so outlandish it’s hard to believe this is something that actually exists, much less has a following.

It’s when Fox takes us inside the minds of his subjects that the real story of The Blackout Experiments unfolds. Eaton and the other subjects walk us through their trepidation and anxiety in the days leading up to their experiences — through a series of emails, questionnaires, and strategically withheld information, the team behind Blackout seem to do as much work building anxiety before their events as during — and the almost addictive reaction many of the guests have afterwards. Blackout appears to be a psychological experience above all else, in which attendees are degraded, suffocated, insulted, and rendered utterly submissive, but they find camaraderie with other "survivors", building a support network to talk about their shared experiences that starts to feel like something out of Fight Club.

That feeling is only strengthened as the harrowing intensity of the sessions is ratcheted up, and the content becomes increasingly tailored to target the specific fears and foibles of each individual. Fox captures these later events in increasing amounts of detail, from invite-only shows, and eventually to a terrifying in-home assault his main subjects receive that is designed to convince them they don’t need Blackout shows at all to help them confront their darkest fears.

Even if it was all fabricated, it would still make for fascinating viewing, but Fox and his team insist that the documentary is "100 percent real" — and having seen Eaton speak after a screening of the film, it seems very much to be the case. Of course, the film was made in conjunction with Josh Randall and Kristjan Thor, the creators of Blackout, and could no doubt be criticized as a commercial for the shows (as much as anything that shows attendees being smothered and waterboarded could be considered a commercial). But it’s the subjects of The Blackout Experiments that make the film so compelling, as they struggle with their attraction to the experience, the fear and paranoia it instills in them, and eventually, reach a strange kind of peace and decide to leave it behind.

If that peace will last, however, will be answered outside of the confines of the movie. After the screening I attended, Eaton confessed that he’d been considering attending the next round of shows in Los Angeles, but that he hadn’t bought a ticket… yet.