Your Wild Shape becomes a monstrous predatory persona. While wild shaped, you become resistant to nonmagical bludgeoning, piercing and slashing damage.
In addition, when you hit a creature with a melee weapon Attack while in Shadow Form, you can expend one spell slot to deal necrotic damage to the target, in addition to the weapon's damage. The extra damage is 1d12 for a 1st-level spell slot, plus 1d12 for each Spell Level higher than 1st, to a maximum of 3d12.