Untitled Sighting

I was homeless for two nights. Decided to stay in a gravel pit I sometimes target practiced at. I was sitting there watching a movie on my laptop and my dog was jumping around in the back seat. He finally decided to jump in the front seat and he proceeded to curl up in a tight little ball. This was unusual behavior for him but I thought, I won't look at him maybe he will be good. In about 5 to 10 minutes it was like something pushed the back of the car down about a foot. It was quite the jolt so I looked out the back window, couldn't see anything it was pitch black outside. I listened intently and couldn't hear anything leave, also didn't smell anything unusual. It was, however, very unusual for my dog to show no reaction and stay in the same curled up tight ball. About an hour later I figured I would let my dog out for the last time. What usually takes a while, he did his business and was ready to get back in the car.