Burger King creates 'nightmare' burger with green bun — and says it will actually give people bad dreams

Burger King is getting ready for Halloween by making a burger bun with a difference.

The "Nightmare King" will have a ghoulish green bun and is filled with grilled beef, crispy chicken, bacon, American cheese and mayonnaise.

And Burger King is actually claiming that the Halloween sandwich will induce nightmares, having tested it with 100 people over ten nights. The study revealed a 3.5 time increase in nightmares.

It's the combination of protein and cheese that leads to vivid dreams, according to Dr Jose Gabriel Medina, a somnologist and the study's lead doctor, according to an online release Wednesday. People's Rapid Eye Movement (REM) cycles were interrupted, a time when most people dream.

"Some Burger King sandwiches are the burgers of their dreams. The Nightmare King is the burger of their nightmares," the company wrote in the release.

The green-hued burger will cost $6.39 and will be available in selected restaurants from October 22 while stocks last.

The fast-food restaurant has also created a black frozen Fanta drink called "Scary Black Cherry."

It's not the first time a colored burger bun has been introduced. In 2015, McDonald's limited edition Modern China burger "horrified the internet" because of its gray bun color, while KFC launched a pink bun in the same year.