Cardial Synchronocity

You create a linked bond between yourself another living creature with a verifiable heart/heartbeat unbroken by any magical means. Each heart beats as one with near identical rhythmic precision, as each party receives identical damage, but do not share total hit points. For example, a wizard with 20 hit points cats this spell on a rogue with 18 hp; As the rogue takes damage, so does the wizard taking the exact same. The spell ends only when 1 or both affected targets of the spell dies, or  the original castor switches to a new target. Spell is ineffective against the dead/undead, and/or creatures brought to life by magical means, or nonliving objects.