Your attacks can prevent winged opponents from flying.

Prerequisite(s): Base attack bonus +9.

Benefit: Whenever you confirm a critical hit against an opponent that uses wings to fly, you can forgo the extra critical damage to instead prevent it from flying for a number of rounds equal to twice the critical multiplier of your attack. Opponents that are flying at the time of the critical effect must succeed at a DC 20 Fly check to avoid taking falling damage.