Mind Stealing Ring (3.5e Equipment)
From D&D Wiki
The ring of mind stealing is a very deadly ring. The person who places on the ring must make a Will save DC 20 or have his brain sucked out of their body and become possessed by the ring. The ring will make the wearer do as the ring wants. The ring is Chaotic Evil and will try to kill the host so that another may wear it so that in the end the only thing alive shall be the ring. The ring may sometimes want to keep the body for the purpose of being able to live. Any one that makes the save fall unconscious for 4d4 hours. They ring may attempt to take over only once per person, per day.