Koopa

Koopa, also known as Bowser or King Koopa, is Mario's archenemy and the leader and most powerful member of the turtle-like Koopa race. He repeatedly targets Princess Peach as part of plans to conquer the Mushroom Kingdom and commands troops including Koopas, Goombas, and Piranha Plants. His appearance combines turtle- and dragon-like traits, and he can breathe fire in most games.