Expecto Patronum

Even if you try to avoid magical mishaps and wouldn't step into the Forbidden Forest after dark, sometimes it's handy to master the most amazing defensive spell from the world of Harry Potter – Expecto Patronum – even in the Muggle world. It not only protects you from Dementors and other unpleasant types, but it also conjures up a friendly companion, perhaps in the form of an elegant stag.