Some of the best documentaries — “The Thin Blue Line,” “Marwencol,” “The Overnighters” — begin with an investigation that lights upon something entirely unexpected. They pursue the new line of inquiry and enter a world of mounting revelations.
David Farrier, cohost of New Zealand’s TV3 offbeat news program “Newsworthy,” encountered a similar development in his sleek, wry, and mindboggling documentary “Tickled.” When friend sent him a YouTube video of “competitive endurance tickling” — in essence a group of hunky young men tickling another young man who is bound to a mattress — he decided it would make a fun subject for a story.
What happened next was so strange that he decided to make a documentary about it, co-directed by Dylan Reeve. This bemused perusal of an oddity soon turned into a byzantine, bizarre descent into a world worthy of Thomas Pynchon.
Farrier began poking around for more information about the competition, and requested an interview from the company that hosted it, Instead of a mere rebuff. he started getting messages — from a woman who described herself as the proprietor of the company that put on the competitions — that were increasingly threatening, erratic, homophobic, and balmy. Not one to back down from a bully, he doubled down on his research.
But the woman doubled down on her threats of litigation and her foulmouthed harassment. She sent a trio of representatives to New Zealand to intimidate him. They told him he was getting into something much bigger than he bargained for. These are rich people, he was told, different from ordinary people, above the law.
This was sufficient motivation to send Farrier and his crew to New York, LA, and Muskegon, Mich., to answer their questions. Their research found a tickle fetish and bondage network back to the 1990s that solicited young men, often from impoverished backgrounds, offering money and gifts to appear in the videos. When they tried to back out, the organization would retaliate with all the means available on the Internet, ruining their reputations, implicating them in illegal activity.
By the end of “Tickled” the realm of superficial giggles has long been left behind. Though his lighthearted tone has difficulties keeping up with each new sinister discovery, Farrier has exposed in the least likely setting the network of power and money that preys on the weak with impunity.
Directed by David Farrier and Dylan Reeve. At Kendall Square. 92 minutes. Rated R (language)Peter Keough can be reached at email@example.com.