There are dozens of ethnic minority groups in China have their own folklore: much of which contains valuable historical and cultural information as well as many unique myths.
Historic Chinese Legends, Tales and Idioms
Historic Chinese Legends, Tales and Idioms » Bu Dong Zhuang Dong
The idiom "bu dong zhuang dong" is used to describe someone who pretends to know about something, but is, in fact, clueless. In this video, a man often "bu dong zhuang dong" in order to look smart. Unfortunately, he only adds to his embarrassment when he is found out.