Anyone ever experience a car chasing them?

I was riding through a local park, going the speed limit (or slightly above) of 20 mph when I noticed a car approaching very, very slowly in my mirror. It sped up an then slowed down when it got pretty close. I guess the driver was trying to scare me.

Um... so, what was the point? I didn't get scared. If I was going too slow, he could have overtaken, but he didn't. And then when another car came by, he stopped doing it until it had rounded a corner. This continued for at least 4 miles throughout then entire park.

It was altogether odd. I did report the car - a large white Infiniti SUV - but in IN we don't have front plates, so I never did see the plate. He finally pulled into a boat launch and I wasn't bothered enough to go back to see him on my ride away. I did stop on the loop back though and he wasn't there. IDK.