While a Goomba is the first enemy the player encounters, they were the last object added to Super Mario Bros. They were created after Miyamoto and his team decided that they needed an enemy that could be taken out with a single stomp, as opposed to the Koopa Troopas. Unfortunately, there was very little space left on the cartridge, and so it needed to be as small and simple as possible. They only used a single image, and made a walking animation by flipping it back and forth.