Bellowing Smite

The next time you hit a creature with a weapon attack before this spell ends, dark clouds form around the weapon emitting sounds of thunder audible to creatures within 60ft as you strike. The attack deals an extra 2d6 thunder damage to the target, which becomes visible if it is invisible, and the target sparks with static discharge and can’t become invisible until the spell ends. 

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.