Gobstopper

“Everlasting Gobstoppers!”’ cried Mr. Wonka proudly. “They're completely new! I am inventing them for children who are given very little pocket money. You can put an Everlasting Gobstopper in your mouth and you can suck it and suck it and suck it and suck it and suck it and it will never get any smaller!”

Hence, gobstopper—something that stops the mouth. If you want to stop someone from prattling on, simply stuff a gobstopper in his or her mouth. The Everlasting Gobstopper, a jawbreaker that changes colors and flavors, was the brainchild of Roald Dahl in Charlie and the Chocolate Factory in 1964.