He repeatedly insults Caliban in the play, by calling him a ‘devil’ (1.2.320), a ‘poisonous slave’ (1.2.320) and ‘malice’ (1.2.368). He also instructs the spirits to abuse him with ‘stinging’ pinches (1.2.330). Similarly, when Ariel asks his master for the freedom he was promised after giving him ‘worthy service’ (1.2.246), Prospero tells him to be grateful for his job, and threatens that if Ariel continues to complain he will ‘peg’ the spirit in ‘an oak’ tree until he ‘hast howled away twelve winters’ (1.2.294-6).