Astra’s Arcbolt

A crackling bolt of electrical energy lances out toward a creature in range, forming a sustained arc of lightning between you and the target. Make a ranged spell attack against a target within range. On a hit, the target takes 3d10 lightning damage, and on each of your turns for as long as you maintain concentration, you can use your bonus action to deal an additional 3d10 lightning damage to the target, automatically.

While concentrating, you can use your action to cause the continuous target of this spell to change. Choose one creature within 30 ft of your current target, this creature makes a dexterity saving throw, becoming the new target on a failed save, or breaking your concentration on a successful one.