Spiteful Weapon

You create a connection between the target of the spell, an attacker that injured the target during the last 24 hours, and the melee weapon that caused the injury, all of which must be within range when the spell is cast.

For the duration of the spell, whenever the attacker takes damage while holding the weapon, the target must make a Charisma saving throw. On a failed save, the target takes the same amount and type of damage, or half as much damage on a successful one. The attacker can use the weapon on itself and thus cause the target to take identical damage. A self-inflicted wound hits automatically, but damage is still rolled randomly.

Once the connection is established, it lasts for the duration of the spell regardless of range, so long as all three elements remain on the same plane. The spell ends immediately if the attacker receives any healing.