When hens have teeth
In French there's an old expression to say "never" or "in a very distant future" that goes something like "when hens have teeth". Well, we're now in this very distant future, apparently, as some chickens are now growing teeth!
OK, they didn't initiate it on their own: it took an Anglo-French team of scientists to create these birds, the first to have teeth since birds evolved from dinosaurs 70 million years ago.
Of course, the team's goal is not only to reform the French language, but eventually to design a technique that could be used to cultivate replacement teeth and hair for those who have lost their originals to age or disease.