Rush

Rush is a robotic dog belonging to Mega Man. He is introduced in Mega Man 3, and has appeared in many games since. Created by Dr. Light and Dr. Wily to be an all around support unit, Rush has the ability to transform into various forms. Rush Marine transforms Rush into a small, one-seated submarine, and Rush Jet transforms his legs into jet engines that let him take flight. Rush also has the Rush Coil, which is a spring that pops out of his back and helps Mega Man reach higher platforms that he normally can't access. Other games have him transform into a motorcycle and a drill car, and in the fourth and fifth Gameboy games as a spaceship. In later games, the Rush Adaptor allows Rush to attach himself to Mega Man, allowing him to float, shoot more powerful blasts, and launch his arms as projectiles.