Arc Lightning

You create a bolt of lightning that arcs toward a target of your choice that you can see within range. Three bolts then leap from that target to as many as three other targets, each of which must be within 30 feet of the first target. A target can be a creature or an object and can be targeted by only one of the bolts. A target must make a Strength Saving Throw (if they’re a lightning bender) or an Elemental Affinity Saving Throw (if they aren’t). On a failed save, the initial target takes 10d8 lightning damage and is stunned until the start of their next turn. On a success, half as much damage is dealt. Each bolt that chains to other targets deals 3d8 lightning damage on a failed save and half as much on a successful one. You gain 1 point of exhaustion. At Trained level, the lightning chains 1 more. At Mastered level, you no longer gain a point of exhaustion.