In the AD&D game there was a section on how to use dnd with Boot Hill a western role playing game.If you can take the amulet,it allows you to regenerate like a troll.Hmm ,much better than I remember that item to originally be ,should have made it aring of regeneration.
Isn't Expedition to the Barrier Peaks set in Greyhawk? Also I remember an old Dragon magazine "adventure" set in Greyhawk dealing with the Baba Yaga's magic hut artifact that had all sorts of "out of time" items in it including a tank Rey~