Boomerang Lightning

You create a floating, boomerang of lightning within range that lasts for the duration or until you cast this spell again. When you cast the spell, you can make a ranged spell attack against a creature within 30 ft of the ball.   On a hit, the target takes lightning damage equal to 3d10.

In addition, the boomerang remains in that space and anyone that enters that space or ends their turn there takes must make an acrobatic check, DC 15 or take 3d10 damage.

Finally, each round the spell is up, as a bonus action  you can aim the boomerang at any creature within 30 ft of it's current location.  Make a new ranged spell attack, doing 3d10 lightning damage if it it hits.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d10 for every levels above 4th.