Serpent labret with articulated tongue
The serpent labret with articulated tongue is a gold-alloy body ornament from the Aztec culture of the mid-second millennium AD. Designed to be inserted into a piercing below the lower lip, it depicts a fanged serpent poised to strike, with a bifurcated tongue hanging from its mouth. The tongue, which is moveable and retractable, would have swung from side to side with its wearer's movements.
Source: Wikipedia — Serpent labret with articulated tongue (CC BY-SA 4.0)