Heavy Demonslayer Arm (3.5e Equipment)
From D&D Wiki
Description: The first time your wear this, a dark glove begins covering your hand. Heavy Demonslayer Arms are made from demon bodies. While wearing this, if you aren't a demon or have demonblood subtype, your total level decreases by one, and you gain no benefit from Demonslayer Claws. You can't remove this from your body.
Activation: Activating the Heavy Demonslayer Arm is a swift action. Your arm gets bigger and becomes more demon-like. Because of its weight, you can't use your second hand. The Heavy Demonslayer Arm is considered a two handed weapon. Deactivating this weapon is a free action.
Effect: When the wearer makes an attack against a evil aligned creature, the arm deals 4d6 bonus damage; against good aligned creatures the arm deals 2d6 bonus damage. This damage is treated as though it came from a magical weapon for the purposes of damage reduction.
Effect 2: If you are tripped during your own trip attempt, you can deactivate the Heavy Demonslayer Arm to avoid being tripped.