Blade Lightning

You create a sword made from lightning for the duration. This sword uses the statistics of a longsword and deals an additional 3d6 lightning damage on a hit. You are proficient with this longsword. The sword disappears if you let go of it, but you can call it back to your hand as a bonus action.

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.