Harry Potter and the Prisoner of Azkaban attacked by a big black dog, which Harry has seen several times before. The dog drags Ron through a tunnel under the Whomping Willow into the Shrieking Shack. Harry and Hermione follow, and there is a brief standoff when they find Ron with Sirius Black, who has transformed from the dog. Lupin enters, and they explain the situation to Harry and his friends: Lupin is a werewolf, which led to his friends James Potter, Sirius Black, and Peter Pettigrew becoming animagi. Lupin explains that Scabbers is Pettigrew in his animal form; he has been hiding from Black, whom he had
Magic in Harry Potter books present the idea that the Muggle interpretation of these stories is a distorted version of what goes on in the wizarding world. The magic of "Harry Potter" became the subject of a 2017 British Library exhibition and accompanying documentary. The exhibition, entitled "Harry Potter: A History of Magic", is the first at the British Library to be inspired by a single series by a living author. Witches and wizards need training to learn how to control their magic. With young and untrained children, magic will manifest itself subconsciously in moments of strong apprehension, fear, anger and sadness. For example,