A spectator sport of lightweight proportions is sweeping the globe, but its combatants don't use knives or fists.

They use feathers.

Pillow-fighting is all the rage among urban hipsters these days.

On Monday night about 100 fans showed up at a club in New York City to watch 16 fighters take to the mattresses in a pillow-fight tournament. Pillow warriors with monikers like "Duck Down Decapitator," "Queen of the Gutter" and "The Little Smoker" faced off in one-on-one, head-pummeling battles.

As local rock groups performed in the background, they competed for glory — and for a championship belt made of cardboard.

The rules are simple. Grab a pillow and smash your opponent over the head until he — or she — falls. The matches last about five minutes, but they've been known to go on for as long as 45.

"One knee down, you're still around; two knees down, you're out," creator and promoter Andrew K. Thompson announced at the beginning of the tournament. "Off the mattresses, you're out."

The contestants battled through three rounds, resulting in a four-way championship match-up among "Luna Loveless," "Duck Down Decapitator," "Jihad Jane" and "Tek Support." When the feathers were finished flying, "Duck Down Decapitator" — by day, a computer programmer named Aaron Crichton — was crowned "Master of the Mattress."

Click here to watch video of the match

Contestants are not allowed to punch, kick or touch opponents with anything other than feathers, and pillows cannot be loaded up with rocks, spikes, salt, or shoes.

It would seem to be all in good fun, but there are some who don't see the humor in the pillow-fight movement.

In 2007, Hugo Spindola, then-general counsel for the New York Athletic Commissioner, tried to ban pillow-fighting in the Empire State after organizers scheduled an event there. In a letter to the creator of Toronto's Pillow Fight League, dated March 12, 2007, Spindola wrote: "These types of events clearly do not meet the strict requirements and statutory definitions of either boxing or wrestling … and would be barred."

Ruth Colon, spokeswoman for the New York Athletic Commission, told FOXNews.com that the law technically prohibits any fighting sports other than boxing, professional wrestling and martial arts, but the office, now run under general counsel Jim Leary, has no plans to enforce the rule in this case.

But that wasn't the case halfway around the world back in March, when 60 policemen in Beijing dispersed a group of pillow swingers who tried to set up a random match at an outdoor mall.

Most of the planned fights go off without a hitch, though, and the "sport" is gaining in popularity.

On the same day Beijing cracked down on the pillow fighters — which was designated World Pillow fight Day by The Urban Playground Movement, a loosely organized group devoted to promoting massive play-events in public spaces — thousands of people gathered in 26 cities ranging from Minneapolis to Zurich. Over the last three years, a rash of pillow-fight leagues, mass gatherings and tournaments have sprung up internationally.

"Kelly the Killer" McLaughlin, a dancer who was in New York's competition on Monday, said she fights because she likes the release.

"You don't really get to put all that energy into the world normally. It feels free," she said.

That need for an outlet was the main reason Thompson, a photographer and former professional wrestler, hatched the Punk Rock Pillow Fight tournament in 2005. He said that while the primary goal of the tournament is to have fun, he created the match as a venue for himself and others to release aggression.

Thompson said he suffers from "rage blackouts," the result of growing up in a household with a sick father who was unable to play with him. Swinging pillows, he said, is a release.

Thompson said pillow-fighting is like running full speed along the beach, laughing the entire time. "When I watch people transform, I feel like I'm baptizing them into a second childhood," he said.

Tyler Villard, a New York bartender who said he has participated in 10 to 15 matches, said he fights because "It feels really good to clobber someone without that violence component."

Thompson said he makes little money from the events — tickets are $10 — but he is hoping to take pillow fighting to a new level. He wants notoriety and increased revenues, but he also wants to keep the spirit of the tournament authentic.

With that goal in mind, he plans to keep the cost of the championship belt under $10.

The first one, handed out in 2005, was made of aluminum foil and beer box cardboard. "It's like the wooden wand — you decide is magic," Thompson said. "The goal is for it to be made of nothing. Otherwise, the joke's on us. We're just jumping on our own mattresses."