The Sa sang fan (사생팬) is compound word of 사생활 (private life) + 팬 (fan),
the meaning is the fan who are chasing the private life of the entertainer, a relentless chase and nuisance.
Fans like to monitor each and every star, extreme stalker basis fan, Sa sang fan in person we come to hit the body in the car riding, and Sa sang fan of fans coming to the excessive stalker violence in the sense that life and death, it recently has become a major problem in South Korea entertainment industry.