Koopa Troopa (Red) from Super Mario Bros.

Mario's enemy - Koopa Troopa (Red) from Super Mario Bros. Koopa Troopa is a turtle-like humanoid with shell that comes in green or red. Red-shelled Koopa Troopa patrols a set area without walking off any edges. In Super Mario Bros., Koopa Troopa is the second enemy Mario encountered, directly after Goomba. If jumped on, the Koopa Troopa would recede into its shell, which could then be jumped on and used as projectile with which to attack other enemies. If left alone for too long, however, the Koopa Troopa would right itself.