Goombas are the most common enemies in Super Mario Bros. and most Mario games afterwards. They merely walk forward in a straight line, only turning around when hitting an obstacle, and have no form of attack other than walking into Mario. Mario can defeat them with any of his attacks.
In the game
Goombas are a generic enemy on the Double Drabobo stage. They cannot damage Abobo in any way, and thus are only a threat by being a small target. Abobo is incapable of punching them, but a single kick will defeat the enemy.