Expecto Patronum, or the Patronus Charm, will cast a Patronus, which can appear as simply white vapour, or in more advanced casters, as a silvery-white animal shape. If it takes the shape of an animal, it is called a corporeal Patronus. This spell is used to ward off Dementors, which are the guardians of Azkaban.
The Patronus Charm is a defensive spell that, if performed correctly, conjures a silvery animal form particular to the user. The charm is used to defend against Dementors - where the witch or wizard summons a guardian to shield them.
One of the most powerful defensive charms known to wizardkind, the Patronus can also be used as a messenger between wizards. As a pure, protective magical concentration of happiness and hope (the recollection of a single talisman memory is essential in its creation) it is the only spell effective against Dementors.
1 Harry Potter's Stag
Harry's Patronus, a stag, is certainly the most prominent in the series (and among the best Patronuses in the Wizarding World), as well as the strongest Patronus in the films. Unlike many wizards, he could produce his Patronus at the age of thirteen, with guidance from Remus Lupin.
Foxes are cunning, resourceful and fiercely intelligent – remind you of anything? That's right – we wouldn't be surprised if some members of Slytherin house find themselves with a fox Patronus. Foxes are also highly adaptable and can live in many diverse habitats around the world.
1 Albatross
As the rarest Patronus in the Wizarding World possible, the Albatross represents an enormous bird that flies freely across any sea. This rare Patronus represents those who are simultaneously fearless, optimistic, happy-go-lucky, and ambitious.
A doe. And in his final battle with Lord Voldemort, Harry explained the significance of this to his adversary, and to us: 'Snape's Patronus was a doe,' said Harry, 'the same as my mother's, because he loved her for nearly all of his life, from the time when they were children'.
Harry Potter: Stag
Harry's patronus is undoubtedly the most recognizable. The stag is first seen in Harry Potter and the Prisoner of Azkaban when it saves Harry and Sirius Black (Gary Oldman) from the dementors at the lake.
Lupin explains that Harry is more deeply affected because Dementors work by extracting good memories, leaving nothing but the bad recollections, and Harry has a much grimmer history than anyone else.
While Muggles cannot see Dementors, their draining power is so strong that non-magical people can still sense them.
Her patronus is Voldemort's other snake.
Harry became so enamoured with the spell that he eventually used it to finish off Lord Voldemort. Here's how Harry's relationship with Expelliarmus became his signature – and why that's a good and bad thing.
No. A patronus charm cannot block Avada Kedavra. Only physical objects can block Avada Kedavra. Physically solid objects like table, wall, door, and of course, humans and animals.
Avada Kedavra
Topping the list for the most powerful spells in the Harry Potter universe is no other than Avada Kedavra, Voldemort's favorite to instill his will and fear onto others. The spell itself is a play on Abra Kadabra and is easy to cast by just about anyone in the Wizarding World.
The information in this broadcast will prove extremely heartening to Harry, as he learns that he is not alone in fighting Voldemort. It will, however, inadvertently result in the Trio being captured. We learn later that the doe was Severus Snape's Patronus.
Severus Snape and the Deathly Hallows
He even sent his Patronus to guide Harry Potter to the sword of Gryffindor (a known Horcrux-killer) in a nearby lake.
When asked what shape Draco's Patronus Charm is, Rowling replied that, at least by the end of the sixth book, Draco was not capable of producing a Patronus, as it is not magic routinely taught at Hogwarts.
In order to conjure the avada kedavra curse, you have to want to kill your victim. We all know that Voldemort could easily kill a child without an ounce of remorse... but not Snape. Snape didn't want to kill Dumbledore, and this was why the spell was blue instead of the usual green.
Snape was born to Eileen Prince, a witch, and Tobias Snape, a Muggle, making him a half-blood (hence the name, "Half-Blood Prince"). This is rare for a Death Eater, as remarked in the last book, though Voldemort himself also had a Muggle father.
For the Potter uninitiated, “always” is how Snape explains to Dumbledore in the final book why his Patronus takes the same shape as the one belonging to his long-lost love: Harry Potter's mother, Lily.
2 Harry Potter's Stag
Harry's Patronus has been shown as having the ability to ward off a crowd of Dementors at once, saving his own life as well as the life of his godfather in The Prisoner of Azkaban.
While it's a lot of fun to find out which Patronus each character has, knowing that Hagrid doesn't have one—a fact Rowling revealed during a 2015 Q&A—is actually quite upsetting for fans.