Harry Potter’s Patronus in J.K. Rowling’s Harry Potter series is a stag.
A Patronus is a protective magical projection summoned against Dementors, creatures that drain happiness and produce despair. Harry first successfully casts the charm during his third year at Hogwarts, when he learns it from Professor Remus Lupin. The stag reflects the form taken by Harry’s father, James Potter, who could transform into a stag as an Animagus.
The shape is also connected to Harry’s family history. James’s Animagus nickname was Prongs, while Harry’s mother, Lily, was associated with a doe. Their matching Patronus forms provide an important visual and symbolic link in the story.
Readers sometimes confuse Harry’s Patronus with his Animagus form. Harry is not an Animagus; the stag is the form of his Patronus. His father, rather than Harry, is the character who transforms into a stag voluntarily.