While you're grappled, you become even more dangerous.

Prerequisite(s): Dex 13, Improved Grapple, Improved Unarmed Strike.

Benefit: You have learned to leverage a grappling creature's weight against it. While you're grappled, attacks you make against the grappler using armor spikes, a light or one-handed weapon, a natural weapon, or an unarmed strike deal damage as if the strike or weapon were one size category larger than it actually is.