blood link

You draw upon the mystical currents of blood magic to link yourself and a target creature. You touch a willing creature, and a mystical connection forms between you. For the duration, you can use a bonus action on each of your turns to transfer a portion of your own life force to the target. The target regains hit points equal to [roll]2d8[/roll] + your spellcasting ability modifier, and you take necrotic damage equal to half the number of hit points restored to the target (rounded down).