Item from Dune by Frank Herbert
A hollow tooth containing lethal poison, concealed in the jaw — Dr. Yueh placed one in Duke Leto's mouth as a last weapon against the Baron Harkonnen, turning betrayal into a final act of revenge.
The poison tooth is the weapon of absolute last resort — the tool you use when you've already lost everything and want to take your killer with you. It requires sacrificing your own life: bite down, crush the capsule, and the gas kills everyone in proximity, including you. Dr. Wellington Yueh placed the tooth in Duke Leto's jaw after betraying the Atreides to the Harkonnens. Yueh's wife was held by the Baron, and Yueh traded the Duke's life for the hope of seeing her again. But Yueh was not entirely broken — he gave Leto the tooth as a chance to kill the Baron in their final meeting. The plan nearly worked. Leto crushed the tooth in the Baron's presence, and the gas killed Leto's guard and Piter de Vries, but the Baron — warned by his suspensor-assisted reflexes — escaped with his life. The poison tooth represents the limit case of Dune's political violence: even in death, even in total defeat, a player can still change the board.
Indistinguishable from a natural tooth. The hollow interior contains a compressed capsule of lethal gas — enough to kill everyone in a small room when the tooth is bitten and crushed. The replacement is performed surgically and leaves no visible trace. Even a detailed medical scan might miss it if not specifically looking for it.
Also known as: Leto's tooth, the poison capsule, Yueh's last gift