First it was the belly button challenge. Then came the boobs over belly button challenge. Now there's another 'test' based on a 'scientific study from the U.S.' again and it has gone viral on Chinese social media Weibo. It's called the 'Collar Bone Challenge.'

To recap, this is the belly button challenge. Millions of girls posted selfies showing they can touch their belly buttons with their arm wrapped around their back:

Millions have taken to Instagram to show off they can do it, showing off their slimness:

But if that wasn't enough, now the Collar Bone Challenge is here. It started with Chinese actress Lv Jiarong who successfully balanced 80 coins on her two collarbones while taking a selfie:

Then the Internet followed suit. People started posting pictures of everything and anything that could be balanced on their collarbones:

Brands like Durex China decided to ride on it too by posting a picture of a vibrator balanced on a woman's collarbone:

What's next we wonder? Here are some more Instagram shots of the Collar Bone Challenge: