Koopa Troopa is a common enemy in the Super Mario series that resembles a turtle. It walks around on it's two feet and if tapped twice on it's shell, Koopa Troopa will spin around trying to home into the nearest person. They originally walked on four feet which is rarely seen these days. Usually, a Koopa Troopa has a green shell, but there are also red and blue variants as well as Dry Bones, a skeleton Koopa Troopa. Their Koopa Shell can be used as items.