Everyone knows what it’s like to be tickled. What starts out as innocent fun, after enough time, quickly turns into convulsing bodies, possessed with uncontrollable hilarity.

This lack of control is also what tickling inherently requires: vulnerable people who are defenseless victims to it.

In the new documentary “Tickled,” journalist David Farrier reveals the unbelievable real-life story of “competitive tickling,” a ridiculous premise that only reveals the darker, more surreal story behind it.

“Tickled” starts out in light-hearted fun, in which Farrier (who stars in and directs the doc), looking for a new story, discovers the world of “competitive tickling.” After a message to the organization, he receives a response back from a mysterious woman, saying that the organization would rather not associate with him, being an openly gay man. Farrier doubles down and throws himself into the world, where fake names, false fronts for non-existent companies, and threatening blackmail lie dormant.

The early premise is entertaining until a group of lawyers travel from the U.S. to Australia (his home-turf) to meet with Ferrier to dissuade him from pursuing any further. It’s here where the tone shifts, and where things lessen in humor and grow in intrigue and mystery.

It’s this tonal shift that makes “Tickled” so compelling. Ferrier and a cameraman colleague travel to the U.S., where they locate and attempt to enter a “competitive tickling” match. This leads to his own harassment some days later from the desk of the same woman who had threatened Ferrier before, as well as countless other unsuspecting victims who had signed up for these events, only to have the entirety of it held over their head as blackmail.

What ultimately keeps “Tickled” from affecting further is that it seems to end short of concrete resolution. Investigative documentaries like Netflix’s “Making a Murderer” and HBO’s “The Jinx” almost seem to come loaded with justice-laden endings, but it’s to Ferrier’s novice documentary experience that we don’t ultimately witness any further justice being served. The final act does amount to Ferrier finding the person behind it all, but after so much build-up, the finale leaves viewers just short of satisfying conclusion. But for those looking to have not just their funny bones engaged, “Tickled” offers a bit more behind the surface.

“Tickled” is not rated. 92 min. In theaters this Friday.