When I was a kid, I set up two metal rods driven into the dirt with some wire tied to it as a finish line.. The wire sagged more and more each lap as the rods tilted inwards. The last lap, the wire clothes lined me in the neck and ripped out the metal rods.
My GF's oldest kid (10) was riding a customers kart and drove off a small hill only to float, smash, then proceed to crash into a 50 year old cottonwood tree. He got up with his glasses all crooked. I asked if he was OK as I was trying not to laugh.. He said he was fine as he straightened his glasses and limped away, trying not to laugh himself..