It is a golden ring with a black circular gem of unknown origin

This ring will allow you to magically fake your death. Whenever you take damage that would be fatal, or if you succeed on your death saves, you can activate the ring. The black gem will glow blue when the ability is active. You create a dummy copy of your body, while becoming invisible for the next 30 seconds, or until you attack or cast a spell. The dummy, if closely examined with a perception check DC of 16, they will realize it is fake, and the invisibility will run out right then and there. This ability can only be used once per short rest.

Notes: Creation, Deception, Tag