While scuba diving off the Great Barrier Reef, a young college student observes a shark heading in his direction. Without a second thought, he rockets to the surface, and scrambles frantically onto...

While scuba diving off the Great Barrier Reef, a young college student observes a shark heading in his direction. Without a second thought, he rockets to the surface, and scrambles frantically onto his boat. He immediately begins complaining of pain, especially in his joints, before collapsing. What has happened?