Twin Thunders

Prerequisites Dwarf or gnome, defensive training racial trait, Two-Weapon Fighting or flurry of blows class feature, Weapon Focus with both wielded weapons.

Benefits

Once per round, when wielding a bludgeoning weapon in each hand against a creature with the giant subtype, if you hit the creature with your off-hand weapon after you hit with your primary weapon, roll the damage dice for your off-hand weapon twice and add the results together before adding any bonuses. Such extra weapon damage dice are not multiplied on a critical hit.