Koopa Troopas is a recurring enemy in the Mario series. They are turtle-like creatures who hide in their shells when someone stomps on their heads. The koopa troopa is the most common classification of Koopa. Koopa Troopas often troopers in the Koopa Troop. Koopas come in four colors: Green,Red,Blue, and also gold, the green koopas are known to walk off cliffs and can't jump.