A Goomba is a mushroom-shaped enemy that appears in a small number of games in the Yoshi series. They used to be at peace with Yoshi's Island and in the Mushroom Kingdom however they later betrayed them. It's a very common enemy in the Mario series however.
Super Mario series[]
A Goomba in New Super Mario Bros. Wii.
Super Mario World[]
In Super Mario World, there are special types of Goombas called Galoombas (which are referred to as Goombas by the game) that live there. Mario or Luigi can defeat them easily, by jumping or by eating them. There are also Paragoombas in the game.
Yoshi series[]
Yoshi[]
In Yoshi, they appear as a minor enemy in both versions of the game.
Super Mario World 2: Yoshi's Island[]
In Super Mario World 2: Yoshi's Island, they only appear in the level Go! Go! Mario!!. When they're merely jumped on by Yoshi, they are flattened, but still alive and angrier. To defeat flattened Goombas, throw an egg at them. They can be defeated by Yoshi's tongue, eggs being tossed, or being Ground Pounded on.