The Bacterium is a common type of enemy found only in the bonus Worm level. They move in a predictable pattern as they patrol the surfaces of the terrain, rolling along contiguous walls. They do not detach from the walls except when the block they are clinging to is destroyed, for example by a bomb. There are many narrow tunnels and passages in the Worm that can make these enemies very tricky to avoid. Attacking them with the whip will only stun them for a brief period, but to destroy them you must throw an object or attack with a stronger melee weapon (such as the Crysknife).