Bound by Blood

You bind a creature to you through your blood, dealing 1d6 necrotic damage to yourself that can't be healed or halved to mark a creature you see within 30ft for 1 minute. Blood tendrils shoot forth from the wound to the marked creature and dig themselves into the target. The target must make a Constitution Save on a fail, they are Bound by Blood to you, taking 1d12 necrotic damage, then when the target damages an ally(including yourself) it takes 1d12 necrotic damage. Also creature cannot regain health based on damage taken from this effect. If the target succeeds, the damage dealt to yourself stays in effect but you don't have to deal damage to yourself upon attempting this spell again

Scaling: additional 1d12 upon reaching level (5) and another at levels (11, and 17) also can mark 1 extra creature upon reaching level 11. The damage dealt to the caster is scaled by die size upon reaching new Scaling level, at level 5 (1d8), level 11 (1d10), and level 17 (1d12)