I Battle a Sea Serpent; Nothing Happens

I'm on a rocky island in the middle of the sea, shaped like a donut. (There's a name for this shape, but I can't remember it, even now.) Suddenly a fire-breathing sea serpent attacks me, and chases me around and around the island, causing massive destruction, and getting pelted with rocks by me. This type of thing isn't likely to be resolved easily with hand-sized rocks, and it apparently never is. I wake up tired. Spring 2009