Armor of Orthys

The creature you touch becomes wrapped in flames resembling plated armor if they aren't wearing any, or the flames simply coat their armor if they are, creating an ablative shield. The target gains temporary hit points equal to 5 + your spell-casting ability modifier as well as resistance to fire damage if they are not so already. In addition, if the target is hit with a melee attack whilst it has temporary hit points granted by this spell, the attacker takes 1d8 fire damage as the flames leap to defend the target.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the temporary hit points increase by 5 and the damage increases by 1d8 per spell level after first.