Lightning Arrow

3rd-Level Transmutation Spell (Ranger)

Casting Time: Bonus Action, which you take immediately after hitting or missing a target with a ranged attack using a weapon
Range: Self
Components: V, S
Duration: Instantaneous

As your attack hits or misses the target, the weapon or ammunition you're using transforms into a lightning bolt. Instead of taking any damage or other effects from the attack, the target takes 4d8 Lightning damage on a hit or half as much damage on a miss. Each creature within 10 feet of the target then makes a Dexterity saving throw, taking 2d8 Lightning damage on a failed save or half as much damage on a successful one.

The weapon or ammunition then returns to its normal form.

At Higher Levels: The damage for both effects of the spell increases by 1d8 for each spell slot level above 3.

Source: Player's Handbook, p. 292