Wolfgang Amadeus Mozart was a prolific composer who is so famous, you probably only needed me to say "Mozart" in order to know who I was talking about. The Wikipedia entry listing all of the music he composed is exceptionally long and diverse -- there are full symphonies, instrument-specific concertos, serenades, chamber music, and importantly for our purposes today, operas. Despite dying at age 35, Mozart composed 22 such works, including three unfinished ones (but who are we to judge).
And in one of those, he took some time to amuse himself -- at someone else's expense.
In 1785-86, Mozart wrote Le nozze di Figaro ("The Marriage of Figaro"), a four-act opera that is regularly considered one of the best of all time. It opened in Vienna on May 1, 1786, with Mozart conducting and a soprano named Nancy Storace performing the role of Suzette, which Mozart had written with her in mind. Storace, as her Wikipedia entry notes, "suffered a catastrophic failure of her voice" performing an opera written by her brother a year prior, which normally would doom the career of an opera singer. But she had a longstanding friendship with Mozart, so in modern parlance, he did her a solid: as summarized in her Wikipedia entry, Mozart "rewrote passages of The Marriage of Figaro at a lower pitch to help Storace get through her performances." The Marriage of Figaro was a huge success and when Storace moved back to her home nation of England at the end of the year, other sopranos took over playing Suzette.
The Venician-born soprano Adriana Ferrarese del Bene was one of those early replacements for Storace, and it appears that Mozart wasn't so fond of her, feeling she her fame had made her arrogant. As a leading soprano, he had little choice but to work with Ferrarese, though -- if you want to have a great opera, you need great voices. But while Mozart cared what Ferrarese sounded like on stage, he wasn't as concerned about what she looked like while performing. So when Mozart got to work on a new opera in 1789 -- Così fan tutte, or "Women Are Like That" -- he did so with Ferrarese in mind for the role of Fiordiligi.
Specifically, Mozart wanted Ferrarese to perform an aria titled Come scoglio, which you can watch here (not performed by Ferrarese, obviously). It's a beautiful song even if you're not into opera and well worth at least a few of its six-plus minute runtime. But if you're really not enjoying it, fast-forward to 3 minutes in (or just click here). You'll hear -- and see -- that the singer had to show extraordinary range, jumping from high to low notes and back in a short period of time. Mozart included those jumps throughout the piece in an effort to stick it to Ferrarese. According to the book Delphi Masterworks of Wolfgang Amadeus Mozart, "knowing her idiosyncratic attendance to drop her chin on low notes and throw back her head on high ones, Mozart filled her showpiece aria Come scoglio with constant leaps from low to high and high to low in order to make Ferrarese's head appear foolish in the performance." As Opera Omaha concludes, "presumably, [Mozart] took great pleasure in watching her bob her head like a chicken."
Whether Ferrerese knew -- or cared -- that she looked like poultry on stage is unknown.