Mecha Dragon

Mecha Dragon (メカドラゴン Mekadoragon) is a giant robotic dragon that is the first from the final bosses of Mega Man 2. When it appears, it will chase the player breaking the platforms on the way, and in the end of the way he will start battle. He stands in the left corner of the screen shooting fireballs, and touching him is lethal. Stand in the top block to avoid falling in the pit and use Quick-Boomerangs.

He also appeared in Mega Man 2: The Power Fighters and Rockman Battle and Fighters, and small versions of him.

Trivia
A similar dragon, called Eregon, appeared in Mega Man X4, and a sub-boss in Mattrex's stage in Mega Man X5 acts similar to the Mecha Dragon.