Chinese singer and actor Yu Yuhan, 20, publicly lost his temper last week after a "sasaeng" (an obsessive fan known for invading celebrities' private lives) repeatedly yanked at his car door while the vehicle was in motion and thrust a phone against the window to film him. Yu stepped out of the car and swung his fist toward the woman, knocking her phone away without striking her, before shouting "Are you sick?" — a rare outburst for a performer widely noted for his calm demeanour. The incident, which went viral in China, has prompted Yu's fan club to call on his agency, TF Entertainment, to increase security and pursue legal action against fans whose behaviour breaks the law.