The “scary black cherry” slushy at Burger King might just give you two Halloween thrills for the price of one. Of course, that depends on how you feel about drinking something that might turn your poop bright blue or neon green.
It’s not so surprising that the inky black seasonal special is likely to turn your mouth and tongue black while you’re drinking it. More disconcertingly, some down-for-anything fans have also reported post-slushy poop that ranges from blue to green. (And, as with any slushy, there’s always the risk of a brain freeze.) Burger King didn’t respond to a request for comment.
It’s not the fast food giant’s first foray into black foods, and also not the first time customers have reported bathroom consequences. In 2015, a special Halloween Whopper burger with a black bun led to customers reporting an evacuation that was “almost a grass green,” USA Today reported at the time.
Black foods have been having a moment, even outside of the Halloween season. Last winter a café in London tried to break the internet with a vegan activated-charcoal croissant. While it doesn’t actually do much for your insides in small amounts, or taste like much of anything, activated charcoal has also shown up in dramatic black ice cream at Morgenstern’s in New York City and Little Damage in Los Angeles. With regular consumption, or a therapeutic dose administered by doctor, it can have a similar effect to those reported from the black food coloring in the black cherry slushy. “Activated charcoal will cause your stools to turn black,” according to the Mayo Clinic. ”This is to be expected while you are taking this medicine.”
Black food coloring, which is what gives the scary black cherry slushy its distinctive hue, breaks down in the intestines, and the blue dyes mix with yellow-green bile to make blue or green tinted poop, Michael Rice, M.D., a gastroenterologist at the Michigan Medicine Gastroenterology Clinic, told Women’s Health. Some foods like dark leafy greens, beets, and blueberries can have a similar result, he said—an unintended consequence of eating the rainbow.
If the slushy is too tame, Burger King is also currently selling a “Nightmare Burger” with a green bun, a burger patty, crispy chicken, bacon, mayonnaise and American cheese. In a press release the fast food chain bragged that diners quadrupled their chances of having a nightmare after eating one.