Ring of zombiefication
Don't put it on....
At this time all we know is that the ring will raise a dead person into a zombie instantly.
Ersatz suspects that the rings also have the property to allow control over other ring wearers.
On their first adventure the part kills four zombies each wearing a ring. they all seem to be of the same make. An identification spell cast on one of them showed it to be a magic ring of +2 Con. Ersatz believed there to be more to these rings and wanted to further study them. He figured they had something to do with enhancing vitality in some way but not in the same way the Identification spell indicated.
When the cleric accompanying the party fell to a goblin attack, Ersatz thought this could be an opportunity to test the rings abilities and quickly put a ring on the recently killed cleric. This had the effect of instantly raising the cleric into a zombie. The group quickly killed the animated corpse and removed the ring form it.
At this time Javen keeps 3 of the rings and Cora has one on her person.