Big legendary ghost dragon. Like...really big and stupidly powerful because basically all legendaries are. That's why they are legendary. I have only ever read about it in books, but supposedly it was incredibly violent so it was banished to an alternate dimension called the Distortion World. Which is probably why it's rarely ever seen.

[Maybe one day he'll get to see it though.]

Only blue version... I didn't realize there were more games after that.