Burger King in Japan sells the Kuro burger, with buns made from bamboo charcoal, an onion and garlic sauce made with squid ink, beef patties made with black pepper, and black cheese, which is also apparently made with bamboo charcoal.
They have two versions, the one shown, aka Pearl, and a version with lettuce, tomato, onions and mayo, called Diamond. Even Japan’s burgers make Pokemon references!! I don’t think this will ever make it here, but stranger things have happened.
Does the Kuro burger remind you of anything?