Today in Paris, Chanel has convened the troops for a pre-fall show in Paris—a full-scale runway spectacle for a season (if we can even call it that) that designers usually show back at the showroom. No one’s ever accused the label of downplaying what could just as easily be played up, but its latest creation is extravagant even for Rue Cambon: a custom-created, one-of-a-kind J12 watch that’ll be auctioned for amfAR, the AIDS research nonprofit, this Monday. The ceramic J12 Rétrograde Mystérieuse, created by neo-complications expert Giulio Papi, is extraordinarily complex, and, according to the label, the first of its kind. Papi put the crown onto the dial of the watch itself, which causes it to obstruct the movement of the minute hand. That being the case, the minute hand goes in reverse for much of its journey around the face—hence, in retrograde. While it’s on its backward path, the minute readings are supplied by a digital display located in an aperture between 5 and 6 o’clock. (The combination of digital and analog works accounts for the “mysterious” designation, says Chanel.) Sound complicated? That’s just to explain, not to make. What’s less complicated, though, is the good cause: 100 percent of the proceeds—the watch is valued at €260,000—will go to amfAR. Interested gawkers can watch the auction, conducted by Phillips de Pury & Company chairman Simon de Pury, online at ChanelWatchForamfAR.org on Monday, December 13, at 3:30 p.m. Central European Time.