"black-sheep"

Hyderabad: There is a black sheep in every flock, they say. But of late, the number of black sheep in the police force appears to be quite high, with incidents of suspensions and dismissal of police personnel for breaking the law and being involved in immoral, unethical or moral turpitude incidents being reported quite often. […]

This same tune is also used as the basis for such children’s songs as Twinkle, Twinkle, Little Star and Baa, Baa, Black Sheep.