Elemental Shell

When you attack with a projectile, use a spell slot to add one of these types to that projectile:

Fire, Acid, Cold, Lightning, Radiant, Necrotic, Poison, Psychic, Force, Thunder.

When attacking an enemy with resistance to your selected type, deal 1D8 additional damage after calculating damage that is not affected by resistance. Until your action, you gain resistance to your selected type.