Armor of Darkness

A creature you touch is covered in a shroud of dancing shadows for the duration. While the spell lasts, the creature’s AC increases to 16 if it is not already higher. It has advantage on Dexterity (Stealth) checks, it resists radiant damage, and it gains darkvision to a range of 60 feet. If the creature is undead, it has advantage on saves to avoid Channel Divinity effects.

Using a Higher-Level Spell Slot. The armor's AC increases by +1 per spell slot level above 4th.

Adapted from the 3e Forgotten Realms Campaign Setting.