Halloween isn't just a holiday, it's big business, and these days you can buy anything from creepy house decor to limited edition food and drinks geared towards ghouls. It's a great way for businesses to cash in on the spooky season while keeping customers happy. But what if a fast food Halloween item causes a lot of controversy ? Burger King's 2015 Halloween Whopper definitely got a lot of attention, just not the right kind.

This seasonal whopper was marketed as Halloween inspired as its burger bun was a striking jet black color. Many excited customers decided to test this spooky burger out, blissfully unaware that its real spookiness might come in the form of a delayed side effect. It quickly became known that eating this burger can turn your stool green, which was certainly not part of Burger King's marketing campaign.

This phenomenon blew up to the point that #greenpoop started trending on Twitter, with some users laughing it off while others were just disappointed. Why this halloween item has a colorful side effect Although the first few customers may have been panicking after their first bathroom visit, medical experts assured the public that this side effect is not actually a health concern. The combination of colors like blue, red, and yellow to make this burger bun black was likely the culprit of the green stool effect.

Our intestines don't fully absorb food dye which means that the remaining colors can dye the food in our gut. The green color comes as a result of th.