Shortsword of Wounding

(Requires Attunement)
Hit points lost to this weapon can be regained
only through a short or long rest.
Once per turn you can wound a creature you hit.
At the start of each of the wounded creature's
turns, it takes 1d4 necrotic damage for each time
you've wounded it, and then make a DC 15 Constitution saving throw, ending the effect of all
such wounds on itself on a success.