SYDNEY—A group of Australian teenagers have sparked a Gangnam Style-like viral dance craze called the “Harlem Shake”, with their pelvis-thrusting moves inspiring tens of thousands of Internet copycat clips.

The fivesome, from Australia’s Sunshine Coast, have shot to fame with their 31-second clip “The Harlem Shake v1 (TSCS original)”, which has been viewed more than 12 million times since being uploaded to YouTube on February 2.

The video-sharing site said the clip by TheSunnyCoastSkate—which the five Australian skateboarding aficionados shot on a rainy day when they were bored cooped up inside—has led to an explosion of spinoffs.

“As of Valentine’s Day (February 14) the number of ‘Harlem Shake’ videos has increased to around 40,000—based on video title—and those videos now have 175 million views,” YouTube said on its Australian trends blog.

The pelvis-thrusting clip starts with a helmeted man dancing unnoticed in a room full of people to a song called “Harlem Shake” by the up-and-coming Brooklyn DJ Baauer. A few seconds later, a number of people break into a wild dance, shaking and twisting, as the bass kicks in.

The concept originated with a video blogger named Filthy Frank, but it appears to be the Australian version that sent the meme viral.

“We didn’t start the dance… But we put our own input into it which is why I think it went viral,” TheSunnyCoastSkate said on their Facebook page.

Thousands of “Harlem Shake” clips are being uploaded every day, according to YouTube, with workplaces, locker-rooms, groups of soldiers, train carriages and bus-stops full of people swept up in the craze.

Most of the videos feature people in bizarre costumes and various states of undress, progressing from a single masked dancer ignored by the others to a writhing mass of bodies.

TheSunnyCoastSkate boys said they had been astonished by the clip’s popularity.

“I think it’s pretty crazy, I didn’t think anyone would care at all,” 15-year-old high school student Corey Walsh, who appears in the video, told the Courier Mail newspaper.

“Some of the groups like the US army doing it, it’s pretty crazy the way it’s taken off.”

Walsh said he believed the “Harlem Shake” could eclipse Gangnam Style—South Korean rapper Psy’s 2012 online video hit which has been viewed by more than 1.3 billion people—if it continued to spiral at such a rate.

Walsh’s father said the teens hadn’t realised what they had created.

“They got bored, and the rest is history,” he said.