Weibo, China's version of Twitter, is blowing up with images of women putting coins in their collarbones, and there is a trending hashtag for the phenomenon.
According to People's Daily Online, the "rules" state the coin must stand up.
Chinese-language site Sina News wrote putting the coins in the clavicle represents the body as "skinny and sexy." It also calls the collarbone challenge "simpler" than the belly button challenge.
But while these challenges -- first belly button and now collarbone -- may just seem silly, experts say they could pose a danger to some people.
“This social media challenge is dangerous because it stokes comparison and fuels insecurity, especially for people who struggle with disordered eating and poor body image," said Claire Mysko, program director for the National Eating Disorders Association. "NEDA promotes social media challenges that promote body positivity and encourage self-acceptance.”
The organization has a help line -- 800-931-2237 -- for anyone struggling and looking for treatment.
ABC News' Alex Hosenball contributed to this report.