Nokonoko

Koopa Troopas (commonly shortened to Koopas or sometimes Troopas) are anthropomorphic, turtle-like creatures with removable shells that come in many different colors, with red and green Koopa Troopas being the most common. Koopa troopas are usually displayed as foot soldiers of the Koopa Troop, under the direct leadership of Bowser.

(Source: Super Mario Wiki)