Ambivalent (3.5e Equipment)
From D&D Wiki
An ambivalent weapon is neutrally aligned and infused with the power of irresolution. It makes the weapon neutral-aligned and thus bypasses the corresponding damage reduction. It deals an extra 2d6 points of damage against all creatures without at least one neutral alignment. For instance, chaotic good or lawful evil. It bestows one negative level on any creature without at least one neutral alignment attempting to wield it. The negative level remains as long as the weapon is in hand and disappears when the weapon is no longer wielded. This negative level does not result in level loss, but it cannot be over come in any way (including restoration spells) while the weapon is wielded. Bow, crossbows and slings so crafted bestow the ambivalent power upon their ammunition.