TICKLED Tickle torture is awful, but it’s nothing compared to that t-shirt.

I DON'T RECALL at what point in Tickled the narration of New Zealand reporter David Farrier stops being cloying and starts to resemble the soothing tones of Werner Herzog. That’s probably because the film—which starts as a documentary about the silly, innocuous sport of "competitive endurance tickling"—gets very dark very quickly. As Tickled grows more sinister, Farrier’s calm, accented voice becomes a comforting presence, one that helps make sense out of a story that gets stranger by the minute—a guide, if you will, through the wilderness of tickling terror.

As Tickled begins, co-director Farrier introduces himself as an offbeat reporter who’s found his next “wacky” story—a video of young men in Adidas gear stoically eliciting giggles from an unlucky but ebullient athlete on a wrestling mat. But when Farrier reaches out to Jane O’Brien Media—the creators of the video—he’s hit with crass emails, threatened with lawsuits, and told, in no uncertain terms, to stop digging. When Farrier deadpans, “This tickling wormhole was getting deeper,” it’s hard to tell if he’s joking.

But as the film progresses, it becomes clear that tickling videos are (sorry) no laughing matter. By the end of the film, Farrier’s revelation that “This tickling empire is way bigger than we ever imagined” might chill your soul.

Facing conditions usually found in gangster movies—Farrier’s told to “walk away,” co-director Dylan Reeve receives a veiled threat to his family, and witness after witness is too afraid to talk—the filmmakers persevere, ultimately uncovering how unregulated, corrupt, and exploitative the practices of Jane O’Brien Media are. They speak to journalists who began to pry into the shady tickling empire way back in the 1990s, a producer who made videos for O’Brien for years (only to later earn O’Brien’s wrath when he balked at her mistreating “the talent”), and a few brave men who speak to her deep pockets and her hair-trigger rage.

And that’s just the first half. By the end, Farrier and Reeve have been to an industrial district of Los Angeles, the impoverished rustbelt town of Muskegon, Michigan, and the high-rises of Wall Street—where things really get weird. What starts as a quirky documentary with a seedy underbelly ends up more like HBO’s The Jinx, complete with limitless wealth, moral bankruptcy, and self-incriminating twists. There’s plenty I’m leaving out, but one thing shouldn’t come as a surprise to anyone who’s read Savage Love: Staged tapings of athletic young men tickling each other are, well, a sex thing.

One of Tickled’s subjects is Richard Ivey, who runs a tickling fetish website and, unlike the litigious O’Brien, is “more than happy” to talk about his status as a tickling-video titan. Ivey even demonstrates “tickle torture” for the film with the help of a young, fresh-faced man buckled into a chair—and even though the man has, presumably, consented to the act, and is a professional adult actor protected by labor laws, and has agreed to the distribution of his likeness (all in notable contrast to the men in O’Brien’s videos), the act is still unnerving to watch. Red-faced and writhing, he bucks against Ivey’s touch; stripped of its erotic intention, it’s deeply uncomfortable to watch someone scream “Stop!” and “I hate this!” through peals of laughter. What starts as an absurd premise turns disturbing quickly, much like the film itself.

In fact, Tickled’s goofy premise is a great hook, but it almost does a disservice to the deeper issues the film unexpectedly touches on: the rights of sex workers, the exploitation of the poor, online harassment, and what happens when the rich have unlimited funds and no moral compass.

Still, it’s not a film you’ll easily forget. Tickled works just as well as a thriller as it does a documentary—I was simultaneously dying to uncover the truth behind a twisted tickle tycoon, dreading the film’s end, and relishing the suspense. Farrier and Reeve may have stumbled upon a stranger-than-fiction story, but they’ve crafted an amazing documentary, one in which they effectively peel off the layers of an onion with a deeply rotten core.