You fling a dart of darkness at a creature within range. Make a ranged spell attack against that creature. On a hit, the target takes 2d6 cold damage, and on each of your turns for the duration, you can use your action to deal 2d6 cold damage to the target automatically. For every minute while affected by this spell, the target must succeed a Constitution saving throw or gain one level of exhaustion.

At Higher Levels. For every level above 3rd, you can keep concentration for another minute.