When this spell is cast, any time an opponent makes a melee attack against you, you may attempt one melee counterattack at your full base attack bonus (this does not count as an attack of opportunity for the round). You must threaten the opponent in order to make the counterattack; you cannot take a 5-ft. step or other movement before making the attack. The attack does not interrupt the opponent’s action. If you are disabled as a result of the opponent’s attack, you may use the counterattack, but doing so reduces you to –1 hit points. If your hit points drop to –1 or lower as a result of your opponent’s attack, you may not use the counterattack.

If you have a spell effect active that requires a successful melee touch attack (such as poisoned grasp or shocking grasp ), you may use the touch spell in conjunction with the counterattack.