Malfoy, his arm bandaged dramatically, returns to class several days later. During Potions class with Professor Snape, Malfoy sits idly watching other students do his cutting and mixing, while he gossips to his fellow Slytherins about his father's influence on Hagrid's job status. Harry is furious, but is also puzzled by something Malfoy says about how he should want revenge on Sirius Black. Harry ignores him and class progresses as usual: Snape picks first on Neville Longbottom for confusing his potion instructions, and then on Hermione for helping Neville. Harry, Ron, and Hermione walk upstairs to the defense against the dark arts class. Hermione suddenly disappears from sight and is seen, hurrying behind them back at the base of the stairs.
Professor Lupin leads them all into an empty classroom to combat a Boggart that had lodged itself in a wardrobe. As the students file into the classroom, they encounter Snape, who makes a nasty comment about Neville. In response to this comment, Lupin says that he wants Neville to be the first to fight the Boggart. Neville is terrified but manages quite competently to perform the "Riddikulus" spell, in which he transforms the Boggart from the shape that terrifies him most into something that makes him laugh. The students take turns, watching the Boggart try to frighten them but finally fall victim to their laughter as they transform it. When it is Lupin's turn, the Boggart takes the shape of an orb, and when it is Ron's, a giant spider. The class defeats the Boggart successfully, although Harry himself does not get a turn.
From this point on, defense against the dark arts becomes everybody's favorite class. Nobody dislikes it except for Malfoy, who enjoys gossiping about the shabby state of Professor Lupin's robes. Gryffindor House begins practicing Quidditch in the hope of winning the Quidditch House Cup. Halloween nears, signifying the first visit to Hogsmeade. Harry is still distraught at being unable to go, so his friends promise to bring him back lots of sweets. Ron and Hermione agree in their sympathy for Harry, although the rest of the time they argue venomously about their pets, especially one evening when Crookshanks makes another attack on Scabbers.
During the Hogsmeade visit, Professor Lupin invites Harry for tea in his office. At one point, Harry asks why he was not given the chance to fight the Boggart, and Lupin answers that he didn't want Voldemort to appear in the classroom. This is a surprise to Harry, who explains that he was more concerned about the Dementors. Lupin looks thoughtful and says, "That suggests that what you fear most of all is fear. Very wise, Harry." They are interrupted by Snape, who enters the room bearing a steaming goblet, whose contents Lupin promptly drinks. Harry worries that Snape is poisoning Lupin in order to get his teaching position, but the subtle hints he makes are left unheeded by Lupin.
When the students return from Hogsmeade, Harry receives a bundle of candy from Ron and Hermione. He informs them of what he saw with Lupin. They attend the Halloween feast, and on their walk back to Gryffindor Tower, they are horrified to see that the portrait of the Fat Lady, who guards the entrance to Gryffindor, has been slashed, the Fat Lady herself missing. Peeves the Poltergeist is cackling midair during the commotion as he informs them that Sirius Black had attacked the portrait.
When Lupin wants to know what is on Harry's mind, Harry openly asks why he was not allowed to fight the Boggart, and Lupin answers just as openly. This scene reveals a more adult dialogue between Harry and his teachers, illustrating a new element of Harry's maturity and confidence. Furthermore, it reveals a self- knowledge in Harry. He recognizes his weakness and seeks to remedy it. In previous situations, Harry has learned things that he happens to remember in time to use against foes, but never does he seek out this sort of basic self- improvement. In this situation, Harry is beginning to take initiative. Lupin's honesty with Harry's questions is admirable, as is his kindness in handling the delicate matters of Harry's worrying. We already have a respect for his competency with fighting dark creatures. These chapters show the gradual process of Harry being singled out as different from other students. Snape holds a grudge over Gryffindor House, and much of this grudge has been linked historically in past books to Harry being in Gryffindor. Thus, he loves to pick on Harry's friends, specifically Hermione for being a know-it-all and Neville for being incompetent. This maleficent attitude makes Harry feel helpless in a way that only the Dursleys and Snape have the power to make him feel. In most other classes, Harry gets along with teachers quite well. In Defense Against the Dark Arts, he and Professor Lupin carry on a fine rapport, and the only problem occurs when the class fights the Boggart without any contribution from Harry. This is certainly deliberate, and it makes Harry feel weak and ashamed, as if he were perceived as not strong enough to take a stand against his greatest fear. Harry is singled out a third time when he is the only third-year student who is not allowed to visit Hogsmeade over the weekend. It is significant of Harry's age and fields of concern that when he overheard Ron's father saying that Black was after Harry, Harry's first thought was not fear for his life, but rather a dull realization that he would never be allowed to Hogsmeade in these circumstances. Being included in these sorts of adventures means a great deal to Harry, and his feeling of defeat as he sits down to converse with Lupin must be considered.