In the excerpt from the book "Invincible" by Sherrilyn Kenyon, a humorous exchange takes place between two characters, Nick and Acheron. Nick expresses his shock about being startled by Acheron, suggesting that he should announce his presence with a bell to avoid scaring him in the future. This comment highlights Nick's surprise at being approached so quietly.

Acheron responds playfully, teasing Nick about his reaction. By saying he didn't know Nick was easily startled, Acheron lightens the mood, implying that Nick's reaction is overly sensitive. This banter illustrates their camaraderie and adds a humorous layer to their interaction, showcasing the dynamics of friendship and the playful teasing that often occurs between close friends.