The boggart — the embodiment of your greatest fear, which can only be defused with humor — is the whole film in miniature. Prisoner of Azkaban has all of the series’ scariest moments so far (the Grim, the Dementors) and many of the broadest (Harry’s balloon of an aunt, the Knight Bus, scaring the Slytherins with the invisibility cloak, every single second Emma Thompson is onscreen).

The boggart assumes many forms, and so do most of the characters this time; the werewolf and the various animagus. (There is also a theme of doubles, which includes Hermoine’s subplot.) The whole movie is about confronting the terrors of the adult world (bodily transformations make an effective puberty allegory), and learning to live with them.