Social media users are setting themselves on fire as part of a dangerous new challenge making its way around the Internet.

The "fire challenge" involves users -- mostly kids -- covering themselves in flammable liquid, lighting themselves on fire and posting videos of the whole ordeal.

Police say a 12-year-old boy from Queens doused himself with rubbing alcohol and lit himself on fire in his Far Rockaway home Wednesday night. Moments later, he was fighting for his life.

He's being treated at Nassau University Medical Center's burn unit for third-degree burns on 40 percent of his body. 

The challenge has a multitude of painful consequences, according to Chief John Murray, a safety instructor at the Nassau Firefighters Museum.

"It destroys all the tissue, and when they're breathing and screaming, they're getting inhalation burns," Murray says. "They're getting that heat into their noses and throats, and that seers the lungs."

The results can often be fatal, according to Murray.

"People who think this is funny should rethink it," he says. "Young children heed the warning: This is not smart."