Took my 2015 Expedition in for an oil change at the Ford Dealership. The service technician came into the waiting room and said he had something to show me. Great, what now. When he was rotating the tires he happened to see something sticking out of the exhaust, end of the muffler. He started pulling on it and it kept on coming. A black and gray silk like material. Every mechanic in the shop ended up over at the car looking at this, having not seen it before. They pulled enough out to fill a small garbage bag. Only thing they could think was some type of sound deaden material. I don't know how this car ran with this packed in the muffler and exhaust, they used pliers to pull it out. Strange