This ability must be cast after combat has already begun. When cast, your main weapon flies out of your hand and attacks your current target. Generally, it does as much damage as a round of combat in which you did not miss. The weapon MIGHT return to your hand when the spell is complete. Or it MIGHT fall to the ground, where it will be subject to scavengers, stompers, and the infamous imp... There are no reimbursements for weapons that you lose with this spell...
Syntax: cast 'dancing weapon'.
See also: Kinetic Weapon Control