Elemental Aversion

You weaken the elemental resistance of one creature that you can see within range. You choose acid, cold, fire, lightning, poison, or thunder for the element they become weak to and the target must make a constitution saving throw. On a failed save, any time the target takes damage of the chosen element they take 1d6 extra damage of that type. If the target creature is immune to the chosen element they automatically succeed on their save.

At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d6 for each slot above 1st level.