Puck, or Robin Goodfellow, is a character in William Shakespeare's play, A Midsummer Night's Dream. Based on the Puck of English mythology and the púca of Celtic mythology, Puck is a mischievous fairy, sprite, or jester. He is the first of the main fairy characters to appear, and he significantly influences events in the play. He delights in pranks such as replacing Nick Bottom's head with that of an ass.