Mob

Mobs are non-player characters (NPCs) which take the form of clones of the default skin, created by pressing 'G' whilst playing in single-player mode. If the player has a custom skin, any mobs created will still be of the default skin, and not assume the look of the player's skin. They cannot create or delete blocks, but just move around the map randomly. They respond the same as the player would to in-game conditions, in that they are affected in the same way by blocks and fluids as the player.