Azareck's String of Fate

Tie together the fates of your enemies with your own, forcing them to share in your pain and suffering until they die, or you do. Choose 1 creature in your line of sight, the target must make a Wisdom saving throw or be effected for the duration. The target must share in the damage that you take until one or both of you die. Whenever the target takes damage, the damage is halves and the target takes the half of the damage. If the caster is effected by a magical effect they can move the effect to the target using a bonus action. If the target dies during the duration you can move the string to another target; and the new target must make a Wisdom saving throw. 

At Higher Levels: When you cast this spell at 7th level the duration is 24 hours. When cast at 8th level the spell lasts 30 days. When cast at 9th level the spell lasts until dispelled.