An anonymous pal sends in this very creepy eBay auction, for a device known as a "scold's bridle." I'm just gonna lift right from this here Wikipedia article where I just learned what that term means.
A scold's bridle, sometimes called brank's bridle or simply the branks, was a punishment device used primarily on women, as a form of torture and public humiliation. It was an iron muzzle in an iron framework that enclosed the head. The bridle-bit (or curb-plate) was about 2 inches long and 1 inch broad, projected into the mouth and pressed down on top of the tongue. The "curb-plate" was frequently studded with spikes, so that if the tongue moved, it inflicted pain and made speaking impossible. Wives who were seen as witches, shrews and scolds, were forced to wear a brank's bridle, which was locked on the head of the woman.
The eBay seller notes that "it was a seriously unpleasant contraption." He models the device in one photo. He wants $1800, which does seem a bit steep without knowing its age, or whether it's a reproduction.
He's selling a male "anti-masturbation" metal chastity belt, too. Thank goodness he didn't model that one.