KNOCK DOWN [Combat]

     Your mighty blows can knock foes off their feet.
Prerequisite: Improved Trip, Str l5+, BAB +2.
Benefit: Whenever you deal 10 or more points of damage to your opponent in melee with a single attack, you may make a trip attack as a free action against the same target.  Use of this feat cannot be combined with Improved Trip to generate an extra attack, and successful use of this feat does not grant an extra attack through the Cleave or Great Cleave feats.