In Harry Potter and the Prisoner of Azkaban, Professor McGonagall reveals her animagus form to be a cat.
Professor McGonagall is one of the four Heads of Houses at Hogwarts School of Witchcraft and Wizardry. She is the Head of Gryffindor House and is also the Transfiguration professor. Her animagus form is a tabby cat, which is revealed to Harry, Ron and Hermione in the Prisoner of Azkaban. Professor McGonagall is known for her strict and no-nonsense attitude, but also for her loyalty and kindness.