Illinois’s greatest restaurant conglomerate is the creator of the world’s most mysterious sandwich. Somewhere in McDonald’s Oak Brook headquarters, someone knows why the McRib is back and when it will again disappear. It’s a mystery to the rest of us.

Finally, some data from Willy Staley (whom I’d never heard of before but now will follow avidly).

The blue line is the price of hogs in America over the last decade, and the black lines represent approximate times when McDonald’s has reintroduced the McRib, nationwide or taken it on an almost-nationwide “Farewell Tour” (McD’s has been promising to get rid of the product for years now).