SRD:Rod of Besiegement

Besiegement
This rod functions as a +3 light mace. In addition, it is useful for besieging fortifications. Whenever the wielder makes a charge attack, the rod improves to a +6 weapon. Twice per day, the rod can create a battering ram that lasts for 24 rounds. This ram can strike once per round, dealing 20 points of damage with each hit. It cannot be used to target individuals, only fortifications. It can be damaged by normal means (65 hp, AC 22), and disintegrate or dispel magic destroys it. The rod also has the following powers:

Siege Engine: One heavy catapult, two light catapults, or three siege towers may be generated with each use of this power. Each weapon created lasts for 12 hours. The power can be used three times per day. Ammunition for 20 shots is included with each weapon created.

Transmute Rock to Mud: This power can be used three times per day (caster level 24th, save DC 17).

Caster Level: 24th; Prerequisites: Craft Rod, Craft Epic Rod, Craft Magic Arms and Armor, clenched fist, passwall, telepathic bond, transmute rock to mud; Market Price: 447,745 gp; Cost to Create: 224,025 gp + 14,474 XP.