Aura of Rainbow

Choose a creature you can see within range. That creature gains resistance to a damage type based on a color you choose.  If you choose red, the damage type is fire. If you choose orange, the damage type is acid. If you choose yellow, the damage type is lightning. If you choose green, the damage type is poison. If you choose blue, the damage type is cold. If you choose violet, the damage type is thunder. In addition, whenever that creature makes a melee weapon attack, they deal an extra 1d6 of the choosen damage type.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, you can target one additional creature for each slot level above 1st.