Acid Armor

You touch a creature and command acid to surround and protect them. This grants them a +1 bonus to their armor class for the duration, and any time that creature is struck by a melee attack it deals 1d6 acid damage to the attacker.

At Higher Levels. If you cast this spell at a 4 level spell slot, the AC bonus increases to +2 and it deals an additional 2d6 acid damage. If you cast this spell with a 6 level spell slot the AC bonus is +3 and it deals an additional 4d6 acid damage