The Cyclone is a mech created by Miles "Tails" Prower. It is actually the Tornado 3 transformed into a mech with legs and cannons. It is first used by Tails in Sonic Adventure 2 to save Amy from Eggman's Egg Walker. It then becomes Tails' main vehicle for the rest of the game.
The Cyclone was armed with a lock-on missile launcher very similar to that of E-102 Gamma along with a powerful gun known as the Volkan Cannon. It could also be upgraded with several new features, including the Laser Blaster, which increased the firing radius and missile explosion sizes, the Booster which allowed the Cyclone to slowly float downwards and hover for short periods, and the Bazooka which makes the Volkan Cannon stronger. It also could transform into a car used by Tails to chase down the President's limo.
In the fight with Eggman, both mechs are destroyed and Eggman takes it's Yellow Chaos Emerald. It is rebuilt as a ship powered by a Dimensional Buffer in Sonic Chronicles: The Dark Brotherhood. It is used to navigate around the Twilight Cage, but is finally shot down by Eggman's cannons.