You bring into being a tiny blade of force. The blade flies at a speed of 40 feet (perfect) and attacks any target within its range, as you desire, starting in the round when you cast the spell. The blade attacks on your turn once per round, striking with an attack bonus equal to your base attack bonus + your Intelligence bonus or your Charisma bonus (for wizards and sorcerers, respectively; if you are a cleric, the blade's attack bonus is equal to your base attack bonus + your Wisdom bonus) and deals 1d4 points of damage, with a critical threat range of 19-20. If an ally also attacks the creature, the blade moves on your turn to flank the target. As a force effect, it can strike ethereal and incorporeal creatures. The blade cannot be attacked.