The eccentric rock was a type of weapon manufactured on Xia; the eccentric boulder was a larger variant of this weapon. The eccentric rock was a rock with a hollow center filled with a type of sticky protodermis. When thrown (or catapulted, depending on the variant), the eccentric rock would explode upon impact, splattering the target with the protodermis inside. The protodermis then formed a cage around the target, effectively trapping the enemy. The eccentric rock could only contain a small amount of protodermis at a time, and the effects would normally not last beyond an hour. The effects of the larger eccentric bolder could last slightly longer. The eccentric rock's name came from the fact that the cages produced by the protodermis inside were always strange and eccentric-looking.