On the way to work this morning I had quite an unusual experience. I was driving along 99S by Greenlake and some dude in an old black Nissan Pickup came up behind me real fast and proceeded to get in my bubble (3-5ft from my tail) and sit there. I pulled into the right lane at the first opportunity I had (probably about a quarter of a mile later) to let the guy pass and he pulls alongside me and proceeds to throw something at my car. It thudded off the left rear quarter and left a small dent and some scuff marks. I got his license plate. I'm not even mad, I just don't get what I did wrong or why I deserved to have something thrown at my car. What are my options going forward?