He suddenly began having a hard time breathing as his neck began to feel strange. He felt dry and felt the need to be wet. The weather was nice enough so he decided to go down to the pool.
"Hmmm... nothing yet." He thought to himself, thouch he could feel a warm, uncomfortable feeling behind his ears. There was no one around to see and he needed to cool off and be hydrated so he just stripped down without bothering with a swimsuit. He dove and immediately felt much better but strangely he could breathe! He was breathing underwater from the very spot behind his ears that was warm before. It was wonderful but suddenly more changes became apparent. His legs began feeling warm, and his spine seemed to be moving withing him, getting longer. His tailbone suddenly poked out from between his legs and his legs began to lose rigidity. His new tail grew thicker as his legs fell away and turned into fins below his crotch. His genitals pushed forward by the new tail settled in a slight depression created by his crotch as new fins grew beneath his now more flexible knee bend and a pair of tail fins looking like some strange cross between that of a shark and a dolphin grew at the end. He inspected these changes with great pleasure and then rose to the surface giving a dolphin leap and letting out a whoop of pleasure. He happily frolicked in his new form.