Bite of Lightning

Select target creature to be the center of a circle with 15 feet radius. target creature along with creatures inside the circle must make a Dex save. The spell does 5 D6 lightning damage on an unsuccessful Dex save. On a successful Dex save the creatures take half damage. If you choose to hold your concentration of casting of the spell it begins to charge and you must declare when you are casting the spell for the first time. Each turn after casting you must choose to cast or hold your concentration to continue charging which will increase the damage and radius of the circle. The circle increase by 5 feet radius per turn you charge it going up to a max of 25 feet radius. The damage will increase by one D6 until the spell is at its max. Then the special does max damage of 8 D6 lightning damage. 

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d6 for each slot level above 4th.