Kamegoro Maker

Turtle Machine (Kamegoro Maker in Japan) is the first Wily boss of Mega Man 3. Despite what happened in Captain N, the actual machine itself is invincible. Enough of the turtles (called Kamegoros in Japan) must be destroyed to cause it to self destruct. As for the turtles, if a turtle is left alone long enough, it will actually shed its shell, turning it into an explosive projectile and causing itself to swim faster.