The Yew Tree Monster (Symbol)
In A Monster Calls, the yew tree monster that visits Conor is a symbol of death and healing. Because most of the tree is poisonous and it grows for centuries, commonly in graveyards, yew trees are associated with death, with some people having believed the tree roots suck poison from graveyard corpses. However, the yew also yields materials that have been used in anti-cancer drugs. As a last resort, Conor's mother's doctors treat her cancer with a drug made from yew trees, but when it doesn't work, Conor confronts the tree about its inability to heal his mother. The tree monster says it has come to heal Conor, not his mother. By listening to the monster's stories, Conor works through the negative and shameful feelings that haunt him. In the end, the monster leads Conor to accept that he cannot prevent his mother's death, and Conor is no longer plagued by dread. The yew tree monster uses its ancient wisdom to teach Conor how to accept death, and in doing so, Conor is healed.
Physical Evidence of Monster Visits (Motif)
After the yew tree monster visits Conor, the monster leaves physical evidence which makes it impossible for Conor to dismiss the visits as simply a dream. The physical trace changes after each visit, from leaves, to poisonous berries, to a sapling growing in the floor. As the motif develops, Conor has to expend increasingly more effort to hide the physical evidence of the visits.
Conor's Nightmare (Symbol)
Referred to as the thing Conor fears most, Conor's nightmare in which he cannot save his mother from falling off a cliff is a symbol for the truth Conor is unwilling to accept. The part of the dream that most disturbs Conor is that he is relieved for his mother to die after the pain he has watched her live through. Although Conor feels relief in the nightmare, in his waking life he feels shame for allowing himself to let his mother go. In this way, the nightmare symbolizes the complex but valid truth of Conor's feelings.
12:07 (Motif)
Starting with the first encounter and occurring throughout the novel, the monster tends to visit Conor at 12:07. Although the first appearances happen at night, the monster also visits Conor in the school lunchroom at 12:07 and helps Conor fight back against Harry. The significance of 12:07 becomes clear in the novel's final chapter, when Conor visits his mother's bedside and sees that the time is nearly 12:07. The reader may infer that she will die at 12:07, but Ness ends the novel before her final moment comes.
The Invisible Man (Allegory)
The monster's third tale tells of a man who became used to being treated as invisible only to grow angry and lash out in anger to make his presence known. As the monster tells the story, Conor acts out his own version, in which he punches Harry in the face. The ironic result is that Conor, like the man from the story, feels even further from the people around him once he has made them see him. In this way, the story of the invisible man serves as an allegory for the human tendency to seek attention, even if it is negative attention, simply to feel seen by people who neglect or ostracize you.
