Crippling Leg Hold (DnD Feat)

Each grapple check you win while pinning your opponent, you can attempt to cripple your opponent.

Prerequisite: Base Attack Bonus +6, Improved Grapple

Benefit: Each grapple check you win while pinning your opponent, you can attempt to cripple your opponent. Your opponent must make a fortitude save against 10 + your grapple bonus, as long as you and the person you are grappling both remain immobile (granting opponents a +4 bonus to attack you). If your opponent fails this save, they take 1d6 ability damage to Dexterity and can not move more than half base speed. Non humanoids get a +5 circumstance bonus to save against this attack and creatures immune to critical hits get a +5 circumstance bonus to save as well. Creatures without limbs are immune to this attack.