Black sludge on Burger King burger

I ordered the Dbl spicy Burger with chips and a drink for breakfast. Luckily i had some chips first ,before eating the Burger.As i was about to take the first bite out of the burger i see this black sludge on the pattie and the bun.It looked like it was coming from the grill.It even stained my nails. I do not recommend going to Clearwater Burger king