Bolting Smite

The next time you hit a creature with a weapon attack before this spell ends, the weapon crackles with astral radiance as you strike. The attack deals an extra 2d6 Lightning damage to the target, additionally, if another enemy creature is within 20 feet of your target you may cause the lighting to chain onto the additional enemy, which takes the same amount of damage as the original target, do not make an additional attack roll.  

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the extra damage increases by 1d6 for each slot level above 2nd.