Ghosts are everywhere!
In a late almost-Halloween post:
鬼 (gwai) literally means ghost, but colloquially it is used in idioms to refer to ‘foreigners’ (people of other races, not Chinese).
鬼佬 (gwai lo), literally ghost man, means foreigner. Though the phrase had a negative connotation to it historically, in modern days it is used more as slang to mean a person of Caucasian descent; similarly used is 白鬼, literally white ghost.