Ball Lightning

A 5-foot-diameter sphere of crackling chaotic lightning appears in an space of your choice within range and lasts for the duration. Any creature that starts its turn within the sphere must make a Constitution saving throw. The creature takes 3d4 lightning damage and cant use its reaction until the start of its next turn on a failed save, or half as much damage and keeps its reaction on a successful one.

At the start of the casters next 3 turns the sphere moves to the space, which the next closet creature within 10 feet of its current position occupies. If there are more than 1 creature to choose from, the DM chooses randomly. (The Ball Lightning prefers creatures that wear or hold a lot of metal, like plate mail or a greatsword).  If there are no more creatures within 10 feet of the Ball Lightning the spell ends early. It cant move through inorganic matter like stone or dirt, but it can move over barriers up to 5 feet tall and jump across pits up to 5 feet wide

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 2d4 for each slot level above 2nd.