Elemental Susceptibility

Choose one creature you can see within range, and choose one of the following damage types: acid, cold, fire, lightning, or thunder. The target must succeed on a Constitution saving throw or be affected by the spell for its duration. The target gains vulnerability to that damage type until the spell ends. This spell has no effect on creatures that have resistance or immunity to the chosen damage type.

At Higher Levels. When you cast this spell using a spell slot of 7th level or higher, you can target one additional creature for each slot level above 6th. The creatures must be within 30 feet of each other when you target them.