A Koopa Troopa is a turtle in the Mario and Mario Kart video games. Most of them work for Bowser (i.e. they are the "bad guys"), but in Paper Mario some of them are on Mario's side, notably a blue-shelled Koopa Troopa named Kooper who helps Mario defeat Bowser. There are many variations of Koopas: some just have different colored shells (green, red, yellow, and blue). Others variations include the Flying Koopa, Paratroopa, and the Hammer Brothers, who are Koopas in heavy armour who throw hammers.
