"I wish...", you start but are then interrupted by the siren singing "join me...", immediately putting you in her grasp:"...to be a merman so I can join her..." You can already feel your leg bones dissolving, turning into weak flesh that shrinks into your body within moments, making your pants drop off you. Your body now has no bottom, and your pants are on the floor next to you. Just as quickly, flesh begins to expand again from your spine, quickly extending into a great length of mass that is under the control of your tailbone. It flakes into thousands of individual scales, attaining all sorts of colors and feeling slick to the touch when you run a hand across it. The tail ends in a point, from which now two translucent fins spring, glittering in the sunlight. Still half-dressed and being a fish from the waist down, you have no option but to obey and start waddling your way towards the pool...