Arrow of Stormsong

You chant a song to Silvanus, and the next time you make a ranged weapon attack during the spell’s duration, the weapon’s ammunition, or the weapon itself if it’s a thrown weapon, transforms into a bolt of lightning. Make the attack roll as normal. The target takes 2d8 lightning damage on a hit, instead of the weapon’s normal damage. The piece of ammunition or weapon then returns to its normal form.

On each of your turns until the spell ends, you can use your bonus action to transform your weapon’s ammunition, or the weapon itself if it’s a thrown weapon, into a bolt of lightning in this way again.

 Using a Higher-Level Spell Slot. The damage of the spell increases by 1d8 for each spell slot level above 3.