The Patronus charm isn’t only an extremely powerful piece of magic, it’s also a deeply personal one. Each Patronus is specific to its wizard and is conjured by focusing on your happiest memory. Used for protection or even to send a message, a fully formed Patronus will take the shape of an animal or magical creature and act as a shield against dark magic, specifically Dementors. Though the spell is traditionally tough to master, it is one of the most powerful tools a wizard can deploy — and befitting to Rowling’s message, it comes from a place of joy and of love.
Top 10 Coolest Harry Potter Spells
From incantations that protect against the dark arts to charms that will stuff a week's worth of luggage into your purse, TIME takes a look at the best spells from J.K. Rowling's famous wizards