The Tongue of Jarthis the Slaver is a vampiric artifact.
Jarthis was a fat Giovanni who existed for a number of centuries. He developed an overwhelmingly lucrative slave trade, especially with the triangle trade of the 1700s. Jarthis had the power to tell lies better than almost anyone, and was able to spot a well-spoken lie with ease. Jarthis was killed in 1823; the Assamite responsible removed his tongue and returned it to the Nosferatu who sanctioned the killing. The Nosferatu used a debt owed him by a Tremere to have Jarthis’ talents of lying imbued in the tongue. It has passed rhrough many hands, and now looks like a dried-up, leathery strip of meat. If a person puts the tongue in her mouth, she can tell a lie without being discovered. If she holds it to her ear, she can ascertain whether or not a given statement is a lie.
Players Guide to the Sabbat, p. 153-154