Witch Bolt

A sustained arc of crackling blue energy leaps from your hand to a creature within range. Make a ranged spell attack. On a hit, the target takes 1d12 lightning damage, and on each of your turns for the duration, you can use your action to deal 1d12 lightning damage automatically (no attack roll). The spell ends if you use your action for anything else, the target moves more than 30 feet from you, or the target has total cover.