Hey man. Not funny. Happened to me once. One of those bloody brain looking ones. I was rolling around in the sand in sheer agony for 15 minutes and not one person stopped to see if I was ok. Not even the lifegaurds. Those useless focks.
I'm glad you got to experience that Archy, it's always been a thought in the back of my mind, like duck diving into a dolphin or a sharks mouth.