In the book "The Last Olympian" by Rick Riordan, a character named Blackjack expresses curiosity about the behavior of pegasi, specifically why they gallop while flying. This whimsical question highlights the playful nature of Blackjack and sparks a moment of light-hearted dialogue amid the story's serious themes.

The inquiry about pegasi's flight adds depth to the fantastical elements of the narrative, showcasing the unique characteristics of these mythical creatures. This moment serves not only to entertain but also to emphasize the blend of humor and adventure that Riordan is known for in his writing.