Crystal Heart

The caster reaches a hand into the chest of their target with attempt to remove the heart. To resist, the target must succeed a Constitution saving throw equal to the caster's spell-casting DC. If the target fails, the caster can now use the heart to control the target's actions on their turn. To resist, the target must succeed a Wisdom saving throw equal to the caster's spell-casting DC. This may be repeated at the start of the target's turn.