TimeZone's Seeking Current

You arc a current of electricity at a creature within range. Make a ranged spell attack against the target. On a hit, the target takes 1d6 lightning damage. As a bonus action on each of your turns thereafter, you can arc the current to another target within 60 feet of the previous, and deal an additional 1d6 lightning damage per target affected by the spell, (each target taking the updated amount of damage) to a maximum of 3 targets affected. If the first target dies, or moves out of range, the spell fails.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the maximum number of creatures affected increases by 1 for each slot level above 3rd.