Bowel movements beware...
Burger King's Halloween burger is providing a serious fright for customers, who have complained that it's turning their poo a ghoulish green.
People have taken to social media to moan (and sometimes jest) about the fast food joint's Halloween Whopper with the hashtag #GreenPoo.
Try the new Halloween Whopper at Burger King! It will haunt your colon.October 1, 2015
The burger in question comprises flame-grilled beef with melted cheese, tomatoes, lettuce, mayonnaise, pickles, white onions and a black-coloured bun topped with sesame seeds.
It is available to buy in the UK and US throughout October.
The spooky-looking bun, which gets its colouring from A.1. Sauce, is believed to be the
The company told ABC News that the black bun contains less than 1% food dye.
The most common reason for green poo is a dietary habit or change, such as being on a diet rich in dark green vegetables. But, according to Healthline, it can also be down to food colouring which doesn't get processed properly.
HuffPost UK has since reached out to Burger King for comment.
Took like three days for my poop to stop being green, but was totally worth it, @BurgerKing— Toasty (@ImHunterStanton) October 5, 2015
My poop has been green since I ate the Halloween Whopper at Burger King the other day... Thanks @BurgerKing— IG: PeteyPlastic (@PeteyPlastic) October 5, 2015
There have been reports that the Halloween Whopper turns your poop green. I can confirm those reports.— Martin Ryder (@itsmartinryder) October 1, 2015
I can confirm green poo too.— Smurgen Bunny (@Smurgen) October 5, 2015