Goombas are common enemies in the Mario series. They are also among the weakest and easiest to defeat. They were once allies of the Mushroom Kingdom, but after Bowser and his troops invaded, they betrayed the Mushroom Kingdom and joined Bowser's ranks. Goombas are often depicted as brown, mushroom-like creatures with sharp teeth and feet. Goombas first appeared in Super Mario Bros. and is the first enemy Mario or Luigi will encounter. In most games, a Goomba's only way of attacking is simply walking into the player's feet. They can be killed by jumping on them, running into them with a Starman, being shot with fireballs, and many, many other methods in the newer games.