You know how take a mouthful out of anyone who tries to overpower you.
Benefit: If you are the target of a combat maneuver you can, as an immediate action, attempt to bite your opponent in addition to any attacks of opportunity or other consequences your opponent might incur from attacking you. This bonus natural attack does not provoke an attack of opportunity itself and deals base damage appropriate for a creature of your current size (usually 1d4 for Small creatures). If grappled or pinned, you can continue to make this additional bite attack each round as swift action on your turn. You gain a bonus on any attempt to break the grapple equal to the damage you dealt with your bite that round.
Pathfinder Player Companion: Goblins of Golarion. © 2011, Paizo Publishing, LLC; Author: James Jacobs, Hal Maclean, and Richard Pett.