SRD:Dancing

Dancing: As a standard action, a dancing weapon can be loosed to attack on its own. It fights for 4 rounds using the base attack bonus of the one who loosed it and then drops. While dancing, it cannot make attacks of opportunity, and the person who activated it is not considered armed with the weapon. In all other respects, it is considered wielded or attended by the creature for all maneuvers and effects that target items. While dancing, it takes up the same space as the activating character and can attack adjacent foes (weapons with reach can attack opponents up to 10 feet away). The dancing weapon accompanies the person who activated it everywhere, whether she moves by physical or magical means. If the wielder who loosed it has an unoccupied hand, she can grasp it while it is attacking on its own as a free action; when so retrieved the weapon can’t dance (attack on its own) again for 4 rounds.

Strong transmutation; CL 15th; Craft Magical Arms and Armor, animate objects; Price +4 bonus.