Xu Xiaodong, nicknamed "Mad Dog", is a Chinese mixed martial artist (MMA) who has been called the founder of MMA in China and is known for taking down fake martial artists. He gained prominence online after he was filmed defeating a self-proclaimed kung fu master in 2017. In August 2019, Xu spoke out on Twitter, Sina Weibo and YouTube questioning the governments reporting of the Hong Kong protests, stating that the Chinese government was running a "smear campaign", and met with human rights lawyer Chen Qiushi who had shared similar views.