the serpent labret with articulated tongue is a gold aztec lip plug from the mid-second millennium ad. made of a gold, copper and silver alloy, it was cast via the lost-wax process; the tongue, cast individually, can be retracted or extended, and swings from side to side with its wearer's movement. the serpent is thought to represent xiuhcoatl. the labret entered the collection of the metropolitan museum of art with a 2016 purchase, and is considered "perhaps the finest aztec gold ornament to survive the crucibles of the sixteenth century".