It's not totally out of left field -- after all, Japan has a penchant for giving even the most mundane food a twist. But making the leap from fried eggs to a "special truffle menu," well, that's quite a departure. According to Eater, "the newest item on offer is Beef Rossini style with liver pie, a dish of New Zealand Beef topped with foie gras and sliced truffles, served with a red wine demi-glace reduction."
Though you've likely never heard of it, it's a French standard. At 1380 yen, or $15, it's fairly affordable, yet...do you really want to eat demi-glace in a booth at Denny's?
After a spin through Google translate, a partial description of the dish reads: "At reasonable prices, luxury food and is waiting for liver pie that'll enjoy a special truffle menu! The New Zealand Beef soft, topped with goose liver pie produced in Hungary, Ashiraimashita sliced truffles. Page Rigorusosu harmony with their rich food, and produce a tantalizing taste. Family and colleagues to dinner with friends in a carefree feeling rich ... a little more than usual interest."
Huh? "Feeling rich" and Denny's aren't terms you usually see together. Perhaps the Japanese have a better sense of humor than we do.