Car problems I face as an immigrant

So for the last week or so, our family hauler has been making an odd clunking sound, but only on turns, and not consistently, though always coming from the rear
I jacked the car up (13 Mazda cx-9) and checked everything underneath, suspension, cv joints, brakes, wheelbearings, everything and couldn't find anything suspicious

Today the wife had to go shopping and I went to make sure the trunk area was nice and clean and there was the problem...my oldest boy had left his wooden shoes kicking around back there

Some things, you Americans just don't get to experience