The basilisk (which for most of the novel is referred to simply as “the monster” because people do not know what it is) embodies two ideas: first, the harmful nature of prejudice, and second, the fear of the unknown. The basilisk, as Professor Binns explains to Hermione and the rest of the Gryffindors, is a monster imprisoned in the Chamber of Secrets by Salazar Slytherin that is meant to “purge the school of all who were unworthy to study magic.” By its very nature, it is a tool of hatred, and it carries out that goal in its attacks: Mrs. Norris is the cat of a Squib (Filch), and Colin, Justin, Hermione, and Myrtle are all Muggle-born students. Rowling uses the basilisk to demonstrate how easily prejudice can escalate into true hatred and even a desire to murder. For example, Draco (who begins the novel simply disliking Muggle-born students) confesses that he wishes he knew who the Heir of Slytherin is so that he could help that person kill Muggle-borns.
Additionally, because so little information is known about what the basilisk is, it also serves as a mechanism that spreads fear. Because it petrifies students it attacks, the victims can’t reveal any information about it and the students create rumors to fill in the gaps in their knowledge. Like the basilisk itself, misinformation and fear circulate under cover around the castle, to the point at which students are afraid not of the basilisk itself, but of what they do not know (i.e., a nameless monster).
The Monster/Basilisk Quotes in Harry Potter and the Chamber of Secrets
“D’you think I should have told them about that voice I heard?”
“No,” said Ron, without hesitation. “Hearing voices no one else can hear isn’t a good sign, even in the Wizarding world.”
Something in Ron’s voice made Harry ask, “You do believe me, don’t you?”
“’Course I do,” said Ron quickly. “But — you must admit it’s weird. . . .”
“Sir — what exactly do you mean by the ‘horror within’ the Chamber?”
“That is believed to be some sort of monster, which the Heir of Slytherin alone can control,” said Professor Binns in his dry, reedy voice.
The class exchanged nervous looks.
“I tell you, the thing does not exist,” said Professor Binns, shuffling his notes. “There is no Chamber and no monster.”
“Riddle might have got the wrong person,” said Hermione. “Maybe it was some other monster that was attacking people. . . .”
“How many monsters d’you think this place can hold?” Ron asked dully.
“We always knew Hagrid had been expelled,” said Harry miserably. “And the attacks must’ve stopped after Hagrid was kicked out. Otherwise, Riddle wouldn’t have got his award.”
[…]
“And Riddle was going to go back to some Muggle orphanage if they closed Hogwarts,” said Harry. “I don’t blame him for wanting to stay here. . . .”
He might not see what use Fawkes or the Sorting Hat were, but he was no longer alone, and he waited for Riddle to stop laughing with his courage mounting.
“I seem to remember telling you both that I would have to expel you if you broke any more school rules,” said Dumbledore.
Ron opened his mouth in horror.
“Which goes to show that the best of us must sometimes eat our words,” Dumbledore went on, smiling. “You will both receive Special Awards for Services to the School and — let me see — yes, I think two hundred points apiece for Gryffindor.”
The Monster/Basilisk Symbol Timeline in Harry Potter and the Chamber of Secrets
