Eustace is a character from C.S. Lewis's fantasy series, "The Chronicles of Narnia." He first appears in "The Voyage of the Dawn Treader," where he is depicted as a selfish and unpleasant boy. Throughout the story, Eustace undergoes significant character development, learning valuable lessons about bravery, friendship, and humility. In the narrative, Eustace is transformed into a dragon due to his greed and selfishness. This transformation serves as a pivotal moment in his journey, allowing him to understand the consequences of his actions. Ultimately, Eustace's experiences in Narnia help him grow into a more compassionate and courageous individual.