Crystal Armor

You touch a willing creature who isn't wearing armor, and a protective crystal coating covers it until the spell ends. The target's base AC becomes 13 + the caster's spell modifier & provides 1d8 + the spell casters level in temporary hit points. The recipient of this spell is resistant to fire, lightning, & radiant damage. The spell ends if the target dons armor, the duration of the spell elapses, or if you dismiss the spell as an action.