Cursed Link

You choose two creatures within range to share a connection between their souls. They both are forced to make a Constitution saving throw; a willing creature can choose to fail. On a failed save, their souls are cursed and linked with each other. If one of them takes damage, the other takes 4d6 necrotic damage, which can't be prevented in any way.

If a creature dies by this spell, you can maintain a connection with the spirit if you expend a 2nd-level spell slot after each long rest. While the connection remains, you can choose the spirit as one of the targets, and it automatically fails the saving throw. You can use your action to deal the spirit damage, thus damaging the other target as the spell suggests. If you do not expend a 2nd-level spell slot after a creature is dead by this spell for more than 24 hours, or if you do not expend a 2nd-level spell slot after other long rests, you must make a DC 15 Constitution saving throw. On a successful save, you can't use the creature as a target for the spell, but the spirit is not destroyed for another day. On a failed save, the spirit goes free.

While a spirit is trapped by this spell, it can't be resurrected. In addition, you can cast the speak with dead spell on the spirit to talk to it.