So im driving back from Hershey on 72/322 last night, and theres a small section where the road becomes uneven from repaving, i hit it at about 65MPH. I hear some clanking and look in my rearview to see some kind of metal plate skid under the car behind me. What's the first thing i thought? License plate. It was only another few miles so i drove home, and checked the plate, and it was still there. No idea if it was mine or the guy in front me, but could it have been a stone gaurd or something?

Maybe it was a heat shield from a catalytic converter?

only way to know is to get under there and look