Download this drawing of a Goomba to color. Goombas are the most common enemies in the series. They appear at the beginning of each adventure and are easy to defeat. Goombas are inspired by mushrooms, specifically a species from East Asia called the Shiitake mushroom ("Chinese mushroom").
The Goombas lived with the Toads in the Mushroom Kingdom, but when Bowser and his army of Koopas attacked the kingdom, the Goombas decided to join Bowser's ranks and betrayed the kingdom and the Toads. Since then they have been known as traitors. In 2D platformers, their way of attacking is simply walking from right to left until they bump into Mario, but in 3D platformers they actively chase Mario.