Armor of the Dead

You touch a willing creature who isn't wearing armor and a bony shell forms over it resembling breastplate armor. A floating shield of bone manifests and moves to protect the target. The armor and shield weigh nothing and cannot be removed by any means. The target's base AC becomes 16 + its Dexterity modifier and does not benefit from wielding a shield. The target gains resistance to bludgeoning, piercing, and slashing damage from nonmagical weapons.

The necromantic essence of this spell drains the life force of enemies who get too close. When a creature affected by this spell takes damage from a melee attack, the attacker takes half of the damage dealt as necrotic. The spell ends if the target dons armor or if you dismiss the spell as an action.