Basset Hound

The Patronus is the most famous (and famously difficult) defensive charm. The aim is to produce a silvery-white guardian or protector, which takes the form of an animal. 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. The majority of witches and wizards are unable to produce Patronuses and to do so is generally considered a mark of superior magical ability.