Dragon was King Pablo's dragon egg, who hatched in the episode "Tale of the Mighty Knights: Part 2". The character acts similarly to a duck. He cannot speak but manages to communicate through noises such as quacks.
Dragon is mostly a light green color, with dark green spots on his back. His horns are dark green with light green stripes. He has two large wings and white eyes with black pupils. On illustrated promotional art, Dragon's horns and spots are light purple.
Dragon has appeared in three episodes of The Backyardigans: "Tale of the Mighty Knights: Part 1" and "Tale of the Mighty Knights: Part 2" from season three, and The Tale of the Not-So-Nice Dragon" from season four. He also appears in the Tale of the Mighty Knights Live! performance.