In "The Last Olympian" by Rick Riordan, a humorous observation is made about the consequences of demigods using cell phones. The quote highlights how the signals emitted by these devices can attract monsters, effectively signaling their presence to any nearby threats. This not only adds a comedic layer to the narrative but also emphasizes the challenges faced by demigods in their battles against various enemies. This situation creates a sense of urgency and danger in their lives, as using a phone can put them at greater risk. It serves as a reminder that even mundane activities, like making a call, can have dire consequences in their world. The blend of humor and peril reflects the adventurous and often chaotic nature of the characters' experiences in their mythological realm.