A character in The Chronicles of Narnia written by C.S. Lewis. Eustace begins as a sarcastic antagonist in The Voyage of the Dawn Treader, tormenting Lucy and Edmund Pevensie about their obsession with the "fictional" Narnia. When he finds himself joining them in Narnia, he has a conversion experience with Aslan after his "greedy, dragonish thoughts" turn him into a dragon itself.
He returns to Narnia with classmate Jill Pole to rescue Caspian's son in The Silver Chair, then again with Pole for The Last Battle of Narnia, at the death of that world.
One of the more unfortunately-named characters in children's literature.