Based on the context and the answer, generate a question. 

Context: The driver slammed on his brakes and the pig ducked , went under and then came out of the other side . He had a little mark on his back and obviously shaken went to the side of the road and knelt down on his trotters . He looked so scared .

Answer:

He was hit by a car .



What may be the reason why the pig had a mark on his back ?