Thousands of people in China are making "finger knots" to show off the flexibility of their fingers.
The "finger knot" requires someone to interlock their digits to form a knot.
Weibo, China's equivalent to Twitter, users have been quick to share pictures of them doing the difficult hand trick.
The new social media craze has spread quickly and caught the attention of the Daily Mail and BuzzFeed.
BuzzFeed even made a video to teach viewers how to do it.
Web users around the world also gave the hand trick challenge a go and shared pictures of their attempts on Instagram and Twitter.
The craze first started when Chinese actor Zhang Yishan was seen making a difficult finger move in a popular TV show, which has had 860 million hits on its Internet pages up to Thursday.
Zhang made the finger move with his right hand, putting his little finger on top of his thumb while keeping the other three fingers straight.
The finger move looks easy, but many viewers said it is 'physically impossible' and the difficulty is to keep the little finger on top of the thumb.
The craze was spurred on by a challenge from Nigerian website KRAKS TV that posted this photo to its Twitter account.
Chinese TV personality Li Sisi posted a photo of her trying the challenge onto her Weibo page and challenged web users to make a knot with their fingers.
Li's followers immediately joined in and created more difficult hand tricks.
WHY SOME CAN AND SOME CAN'T
Dr Jane Simmonds, a registered physiotherapist at the University College London, said those who could perform the difficult finger tricks are likely to have joint hypermobility, a common phenomenon present in 20 to 30 per cent of the general population, according to the Daily Mail's report.
As Dr Simmonds said, joint hypermobility is more common in children and females, and also in Asian and Afro-Caribbean ethnic populations, which may be a reason for the popularity of finger tricks in China.
Daniel Brown, a consultant hand surgeon at The Bone & Joint Centre at Spire Liverpool Hospital, said only a small number of people can do the finger trick that Chinese actor Zhang Yishan has performed.