Professor Minerva McGonagall is a fictional character in the Harry Potter series by J.K. Rowling. Professor McGonagall teaches Transfiguration at Hogwarts (a fictional school for wizards and witches in Harry Potter), and is an animagus. An animagus is a person who has the ability (in Harry Potter) to transform into a certain animal at wish. Professor McGonagall has the ability to transform into a cat. Her cat form is described as a tabby with rings around it's eyes, symbolising her human form's glasses.