A sasaeng is an overly obsessed K-pop fan whose life is dedicated to harassing korean idols and celebrities.
Their typical actions can include following around said idols, stalking, taking photos and videos without permission, entering their private spaces, sending
disturbing messages and sometimes
threatening the idol because of their sick obsession, physically harming other fans and idols. Some sasaengs
collaborate by selling and exchanging to one another private informations. (ex. airport flights informations, house addresses, personal phone numbers...)