Hermione’s Time-Turner (Symbol)
Hermione's Time-Turner, which takes the form of a small hourglass on a golden necklace chain, symbolizes the precious value of time. Even in the wizarding world, where time can be manipulated in ways impossible to Muggles, one of the most important laws of magic is that one must not alter time, because the universal consequences are too unpredictable. The fact that the object which allows Hermione to go back in time takes the form of a precious piece of jewelry reinforces the notion that time is a luxury—highly sought-after and not to be wasted.
The Grim (symbol)
Trelawney proclaims that the Grim is an omen of death, but Harry has been cheating death since he was an infant. He's the only wizard to live after being attacked by Voldemort, and he accomplished that while sitting in a crib. So when a large black dog starts stalking Harry at the beginning of the novel, and when later in the novel a psychic tells him that black dogs symbolize death, we know that if there's anyone who can cheat a death omen, it's Harry Potter. But it turns out that the black dog isn't aiming to hunt Harry; in fact, it's his guardian, his very own godfather. The Grim symbolizes misunderstood fate and prejudice. The image of the black dog has such a negative connotation that no one even considered that it was there to help.
Mystery (Motif)
Though the Harry Potter series falls under the genre of fantasy, Rowling makes heavy use of mystery-novel tropes, and misdirection is a recurring motif in Prisoner of Azkaban. The first mystery established is how Sirius Black could possibly escape Azkaban when no wizard has been able to escape it in the fortress's history. Then, small clues appear as to his connection to Harry. For example, when Mr. Weasley makes Harry swear that he won't seek out Black, no matter what happens or what he may hear, Harry asks the obvious question, "Why would I go looking for someone I know wants to kill me?" (73). This question is also a cue for the reader to start to wonder the same. Why would Harry look for Black? There has to be a reason, and the reason will become clear in time. Other mysteries include questions like, What is Lupin's chronic affliction? or How is Hermione attending two classes at once? All of the book's mysteries somehow intertwine and reveal themselves in the end.
Dementors (Symbol)
The soul-sucking creatures that appear in the third book symbolize fear and depression. The Dementors are large, dark-cloaked figures who feed on the happiness of the victim until there is nothing left in them, not even their soul. The feeling one is left with after just being near to a Dementor is one of coldness and the feeling that you will never be happy again. Harry has a close encounter with more than one Dementor in the book, each time hearing the final scream of his mother playing in his head. J.K. Rowling said she wrote the third book while living with the depression that followed her mothers' death, and personified this feeling into a foul and terrifying creature. This connection is solidified when Ron says, after encountering a Dementor for the first time on the Hogwarts Express, "I felt weird ... like I'd never be cheerful again" (85).
The Rat (symbol)
The fact that Pettigrew's Animagus is a rat is an obvious nod to the animal's reputation as a symbol of betrayal and subordination. At first, Peter chose a rat because it was small and reaches places that others could not, but now that he has settled into the role of a spy for Lord Voldemort, his identity as a rat is quite fitting and permeates his mannerisms even when he takes human form. Black says to Pettigrew, "If you made a better rat than a human, it's not much to boast about, Peter" (373).
