Bob-ombs are living bombs, sometimes with windup keys on their backs. They wander around aimlessly and eventually explode on their own if not picked up, stomped on, or thrown around. They first appeared in Super Mario Bros. 2. Bob-ombs are common enemies in Super Mario 64 as well as allies. In these games, Bob-ombs are first encountered in Bob-omb Battlefield, a level that is ruled by King Bob-omb.