Discharge

You release stored magical energy in a burst of lightning. Choose one creature within range, that creature must make a Dexterity saving throw. On a failed save, the target takes 4d6 Lightning damage. If you are maintaining concentration when you cast this spell, you can choose to end the concentration add an additional 2d6 to the damage dealt. On a success, the target takes only half damage. 

At Higher Levels: When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 2d6 for each slot level above 2nd (3d6 if you end a concentration effect.)