Zurvan's Unwinding

A temporal connection of purplish energy lances out toward a creature within range, forming a sustained arc of time between you and the target. The target must make a Constitution saving throw. On a failure, the target takes 1d12 necrotic damage, and on each of your turns for the duration, you can use your action to deal 1d12 necrotic damage to the target automatically. The spell ends if you use your action to do anything else. The spell also ends if the target is ever outside the spell’s range or if it has total cover from you.