The parasite believes itself to be the host

The parasite believes itself to be the host is Aza Holmes’s formulation of a disturbing uncertainty: feeling like an independent self does not prove that one is directing one’s own life. First grounded in her account of a parasite that alters a fish’s behavior, the idea returns in a conversation with Davis Pickett about adults, power, and Davis’s father. The expression links biological control to Aza’s fear that her own story may be authored by something beyond her will.

The Biological Image

Aza explains the life cycle of Diplostomum pseudospathaceum, which matures in the eyes of fish but can reproduce only inside a bird’s stomach. Infected fish initially swim in deep water, where birds are less likely to spot them. When the parasite is ready to reproduce, the fish begin swimming near the surface, increasing the chance that a bird will eat them. The parasite’s life cycle thus depends on behavior that carries the fish toward its own capture; after reproducing in the bird, the parasites return to the water in the bird’s excrement and encounter fish again.

For Aza, the unsettling point is not simply that the parasite inhabits another creature, but that it appears to direct the creature’s actions. She tells Davis that she feels like the fish, as though her whole story were written by someone else. The image makes agency difficult to distinguish from a sense of agency: the fish can feel pain, but that feeling cannot establish that it controls what it does.

Aza’s Fear of Selfhood

The explanation becomes personal when Aza tells Davis about pressing her thumbnail into her fingertip. The habit began in childhood as a way of assuring herself that she was real: pain seemed to confirm that she was awake and present. She tells him she had not disclosed this practice to Daisy Ramirez, Dr. Karen Singh, or anyone else. The parasite analogy unsettles the reassurance she once found in the sensation, because a fish can feel pain while still being driven by a parasite.

The phrase therefore gathers two questions into one image: whether Aza is real, and whether being real means being in control. Her account does not resolve either question. Instead, it shows why bodily sensation, which briefly reassures her, cannot settle her deeper fear that her actions and life story may be governed from outside herself.

The Phrase and Adult Power

The wording appears later as Aza and Davis drive across the river, with Pirates Island visible below. Davis speaks about Aza’s mother as someone who cares, contrasts her with adults who try to fill themselves with money, alcohol, God, or fame, and describes his own father as someone who had disappeared long before his actual absence. He also argues that adults may believe they wield power when power is in fact wielding them.

Aza answers, “The parasite believes itself to be the host.” Davis agrees. In this exchange, the expression extends beyond the fish-and-parasite example: it gives compact form to Davis’s observation that people can mistake subjection for authority. Its return connects his account of adult power with Aza’s earlier fear of being directed by an unseen force, while preserving the distinction between their circumstances: Davis is speaking about adults and his father, and Aza supplies the biological image that names the reversal.