Adder Stone

This small stone looks to be a chunk of rock with a perfect circle sheared out from its middle. Also know as a "Hagstone", it's believed that these stones are formed from the hardened saliva of a particularly ancient serpent.

While within 100 ft. of a Fey, Demon, or Undead, the stone lets out a dull hum.

As a bonus action, you can peer through the stone and speak its command word. When you do, you can see Invisible objects and creatures when you peer through the stone. Once you use this stone in this way, it loses its magic.

Notes: Detection, Utility, Consumable, divination