Few characters in The Chronicles of Narnia books experience as big of a transformation and character change as Eustace does. From the time he is first introduced in The Voyage of the Dawn Treader, he is seen to be a self-centered and arrogant whiner with no respect for anyone but himself. He calls his own parents by their first names and treats his cousins, Lucy and Edmund, very poorly whenever they come to visit. He thinks very highly of himself and believes everyone else to be beneath him. It would seem that the only thing that could possibly change him would be a magical faraway land and a talking lion.
Eustace Before

When Eustace, Edmund, and Lucy are transported to Narnia through the ship painting hanging in Eustace’s guest bedroom, Eustace is extremely upset about the predicament. He initially refuses to even believe that he is actually in a different world called “Narnia” and on a ship with someone called Prince Caspian. He believes that all he needs to do is “lodge a disposition” once he finds the nearest British court and that he will be able to be taken back home.
However, for the present time, he occupies himself with complaining about every possible thing there is to complain about. He complains that Lucy gets the best cabin on the Dawn Treader just because she is a girl. He gripes about the food rations he is made to live on. And he whines about the perpetual rough seas that the Dawn Treader continues to go through, supposing himself to know more about sailing than Prince Caspian (who is also the captain of the ship) and the crew.
Eustace wanders off on one of the Islands that the ship stops at during its quest, and he falls asleep on a dead dragon’s enchanted hoard of gold. As a result of his “greedy, dragonish thoughts,” Eustace is transformed into a dragon. When he returns to the ship he is nearly attacked by the crew until Lucy is able to deduce his true identity. After he comes to accept his new form, it doesn’t take long for everyone to realize that Eustace has become very different as a dragon.
Eustace After

While still in dragon form, Eustace starts being helpful by finding shelter, food, and a tree to serve as a new mast for the ship. He even befriends the talking mouse, Reepicheep, who he had been cruel to before his time as a dragon. Eventually, Eustace is met by Aslan, who, upon noticing how different he has become, changes him back into a boy.
“It would be nice, and fairly nearly true, to say that ‘from that time forth Eustace was a different boy.’ To be strictly accurate, he began to be a different boy. He had relapses. There were still many days when he could be very tiresome. But most of those I shall not notice. The cure had begun.”
While his character transformation did not happen quite as fast as his physical transformation, Eustace truly did become a completely different boy after his first trip to Narnia. And when he next returned to Narnia, he returned as a hero.
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