The Voyage of the Dawn Treader
by C.S. Lewis
Lord Octesian is one of the seven missing lords of Narnia who were exiled by King Miraz. The travelers on the Dawn Treader conclude that he died on Dragon Island in some way when they find a bracelet with his symbol on it among the dragon's treasures. (This is the bracelet that gets stuck on Eustace's arm when he turns into a dragon.) It's not clear whether Octesian was eaten by the dragon or whether, like Eustace, he himself was transformed into one.