Swimming around a car in the sea

I was in the car with David and his friend Anna. We were driving along the coast and there were large boulder sized rocks dotted along the line where the sea meets the sand. As we slowly drive past one of them.. there is a car in the sea behind it, with water up to the windows. I suggested it would be fun to go swim around the edges of it. Anna agreed but in a sarcastic tone. But when we went over to the car I actually jumped in and swam around the car. I scratched the windscreen and some of the door of the car with a bracelet I had on, but the people inside didn't realise.. they were just smiling and thinking I was amazing.