Eddy

A dragon skeleton used as a jungle gym, called "Bone Hill" by the students. His skull is also often used for secret meetings.

Description
This giant, skeletal dragon's name is just EDDY.. Most of the time, Eddy is fast asleep, and the kids use his body as a jungle gym they often refer to as "bone hill." The inside of his skull is also used as a secret hangout, especially by Yumyum and his gang. We never do learn why he has to be chained up to the school, though. There's even an episode about how homesick he is to be with other dragons somewhere out there in the stars, or maybe he used to be a constellation. It's not really detailed.