Eye of Sseth

This yuan-ti device resembles a thick, heavy gold coin about 2 inches in diameter. One side of it is usually graven with numerals and a device such as a crown, a monarch's head, or the. arms or badge of a country. The other side, however, is a jet-black, glossy serpent's eye. When handled by any Scaled One, an eye of Sseth has no effect - but any other creature that touches it is immediately dosed with poison (contact, Fortitude DC 20, initial and secondary damage 1d6 Con). The poison is gone after one creature handles the coin.
If the last yuan-ti who touched that particular eye of Sseth is still alive, he instantly becomes aware when the eye is first handled by a creature other than a Scaled One, even if it is on another plane. Furthermore, he knows the approximate distance and direction to the spot where the handling occurred and receives a mental vision of the specific creature that touched the eye of Sseth (but not its companions or surroundings). If an eye of Sseth is seized by human adventurers, passed from hand to hand, and then spent in town, the yuan-ti who placed it receives impressions of only the first adventurer who touched it. Eyes of Sseth are commonly placed with scatterings of real coins as 'warning lures' inside the entrances of yuan-ti temples, to warn the inhabitants of intrusion.
Moderate necromancy; CL 7th; Craft Wondrous Item, poison; Price 1,500 gp; Weight 1/10 lb.
Source: Serpent Kingdoms