In "The Last Olympian" by Rick Riordan, a character expresses a powerful metaphor to convey extreme pain. By comparing the agony of jumping into a pit of boiling acid, the character emphasizes the intensity of suffering he is experiencing. This vivid imagery effectively communicates the overwhelming nature of his feelings and the dire situation he faces.

The quote serves to highlight not just physical pain, but also emotional and psychological turmoil. It evokes a visceral response from the reader, allowing them to grasp the severity of the challenges that the characters are encountering in their battle. This kind of descriptive language is a hallmark of Riordan's writing, making his characters' struggles palpable and relatable.