Large and in Charge
( Draconomicon, p. 71)[General]
You can prevent opponents from closing inside your reach.
Prerequisite
Natural reach of 10 feet or more, size Large or larger,
Benefit
When you make a successful attack of opportunity against an opponent that is moving inside your threatened area, you can force the opponent back to the 5-foot space it was in before it provoked the attack of opportunity. After you hit with your attack of opportunity, make an opposed Strength check against your opponent. You gain a +4 bonus for each size category larger than your opponent you are, and an additional +1 bonus for every 5 points of damage you dealt with your attack of opportunity. If you win the opposed check, your opponent is pushed back 5 feet into the space it just left. An opponent you push cannot move any farther in this round.