Malegan

A massive, multiple winged dragon-demon beast, who at some point battles the heroes in the Rise of an Unleashed Army. Because of it's gargantuan size, it is actually the stage players fights on.a

The trophy discription states that it got it's gargantuan size from Zorm's dark magic, and probably was once a mere Baby Yoshi. Zorm made sure that the character, Yoshi, would never discover this information, otherwise the anger would turn Yoshi into a Malegan that could destroy everything, including Zorm. In Character Quest, Yoshi does discover this when fighting Zorm, but overcomes his anger and instead becomes Super Dragon, then engulfs the World of Doom in flames.