The next morning, Harry and Ron are discussing what the dog could be guarding when the mail arrives. Harry receives a first-class broomstick, along with a note from Professor McGonagall summoning him to Quidditch practice. Malfoy tells Harry that first-year students are not allowed broomsticks. When he tries to report Harry to Professor Flitwick, Flitwick just expresses admiration for Harry’s talent. Harry later meets Oliver Wood to learn the basics of Quidditch. On Halloween, Flitwick begins teaching his students how to make things fly. Only Hermione succeeds; Ron, offended by her air of superiority, makes a nasty comment that Hermione overhears. Harry notices her running off in tears.

Harry and Ron arrive at the Halloween feast to hear Professor Quirrell, the teacher of Defense against the Dark Arts, give a terrifying announcement about a twelve-foot troll in the building. As the prefects lead the students back to their dorms, Harry realizes that Hermione does not know about the troll. They head off to warn her and come upon the troll. Unwittingly, they lock it in the girls’ bathroom only to realize that Hermione is trapped in there with the troll. Using teamwork and magic, the three of them manage to knock out the troll. Professor McGonagall finds them and begins to scold the boys. Hermione interjects that Harry and Ron were looking for her. She then lies, saying that she went to face the troll herself and that Ron and Harry had been trying to save her from it. At this point, Hermione becomes their friend.

The troll episode sheds light on the institution of Hogwarts, as well as on various characters in it. It is surprising to see the general alarm created by the sighting of a troll within the castle walls, where so many bizarre and somewhat frightening creatures reside. Professor Quirrell is even more flustered than usual by the sight of the monster, and the students are rushed off to the safety of their dormitories. We see that despite the Hogwarts professors’ great mastery of magic, they are far from invincible, being frightened by a troll of striking stupidity. We may wonder why one of the wizards does not simply put a spell on the castle to prevent trolls from entering or immobilize the intruding troll with a charm. Yet they do not, thus displaying the limits of their magic. Aa Harry is in a position to be awed by the majesty of Hogwarts, this timely show of the Hogwarts staff’s vulnerability is a reminder to him that even the eminent academy may need his help—as he indeed discovers soon enough.

Harry’s victory over the troll is his first true achievement at school, and its symbolic importance is considerable. Furthermore, the troll incident casts a suspicious light on Professor Snape, whom Harry notices sneaking off toward the third floor. Especially in light of Harry’s belief that Snape hates him, Snape’s sneaking away reinforces Harry’s growing belief that Snape is evil. Finally, Hermione’s character develops in the troll scene. For the first time, she breaks out of her overeager, goody-two-shoes role and lies to a teacher. By dropping her perfectionist facade, she appears more human to Harry and Ron. Her willingness to lie to protect her classmates makes her a much more likable and sympathetic individual, which enables Ron and Harry to become friends with her.