From the Science Museum London:
A ‘Scold’s bridle’ is a fearsome looking mask which fits tightly on to the head. A scold was defined as a “rude, clamorous woman.” The bridle was used as a punishment for women considered to be spending too much time gossiping or quarrelling. … The custom developed in Britain in the 1500s, and spread to some other European countries, including Germany. When wearing the mask it was impossible to speak. This example has a bell on top to draw even more attention to the wearer, increasing their humiliation.
"OK, but then what if we added a bell?"