A "heel turn" in professional wrestling is when a "good guy" turns into a "bad guy" (a heel). A "(baby) face turn" is when a "bad guy" has a change of heart and becomes a "good guy" (a babyface).
Have you known any good people who overnight turned into bad people? Or any bad people who overnight turned into good people?
Have you known any good people who overnight turned into bad people? Or any bad people who overnight turned into good people?