Elemental Reflex

When you are hit by an attack or targeted by a spell, you can use your reaction to summon a burst of elemental energy to protect yourself. Choose one of the following types of elemental damage: fire, cold, lightning, or acid. You gain resistance to the chosen damage type until the start of your next turn, and the attacker takes 1d6 damage of that type.

The spell's damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).