Cannonball
Cannonballs are heavy metal spheres that are launched from cannons at high speeds. Mario and Luigi were able to stop the lethal shots by stomping them in mid-air; they could also be dodged relatively easily. They appear most prominently in Super Mario Bros. 3 where they are fired from cannons mounted on Bowser's tanks, boats, and airships.
In the game Mario is Missing!, Luigi had to return the cannonball of the Emperor's Cannon to the Kremlin. It had been stolen by Koopa Troopas.
Cannonballs reappear in Super Mario Galaxy with a more technological appearance. These newer projectiles sport a white line around their center and two yellow circles on opposite sides. In this most recent appearance cannonballs are still fired from cannons, most of which are located in the Battlerock and Dreadnought Galaxies. One notable difference with these cannonballs is that rather than simply colliding with the hero they explode upon impact. This will knock down the victim and stun them for several seconds; it may also result in the unfortunate target being thrown off a platform or into a black hole.
