Percy reflects on the concept of phantom pains experienced by amputees, where individuals feel sensations in limbs that are no longer there. This metaphor resonates with him, illustrating how the absence of certain memories creates a similar discomfort within his mind. These memories, though missing, leave a lingering ache, emphasizing the emotional impact of loss and forgetfulness.

In "The Son of Neptune" by Rick Riordan, Percy grapples with the struggle of not recalling important aspects of his past. The comparison to phantom pains serves to highlight the depth of his disorientation and the intangible yet profound effects that missing memories can have on one's sense of self and identity.