Bond of torment

You weave a thread of dark magic which binds a creature's soul to yours. As a bonus action, you can force a creature of your choice within range to mage a wisdom saving throw. On a success, the spell ends. On a failed save, the target is bound, and on that turn, and every other turn while the spell is active, you can use your action to deal 1d6 necrotic damage to yourself, and the bound creature takes necrotic damage equal to three times the necrotic damage you take.