The hoop rested in your hands as your eyes glanced over its intricate design. The surface was a clear, aquatic dark blue color with silver accents across that gave the appearance of scales. At the very end would be a little ornament in the shape of a fish tail that was made out of a shiny silver material that originally had caught your eye. The package that the hoop had came in was a bit concerning, as unlike the others, it came with a rather large notice near the left corner of the box.
"WARNING: BEFORE USING, ENTER A LARGE BODY OF WATER TO AVOID RISK OF INJURY."
A strange warning, but you did know of a beach that was nearby that was the largest area you could use the hoop to your hearts content. After taking a once over of the rest of the available hoops, you settled on the aquatic one and paid for it in full. After you hurried to your car, you made a drive to the beach nearby. It was in the middle of a work day, which meant that you would have some privacy as opposed to a lot more onlookers watching you.
Arriving at your destination, you soon felt the warm sand beneath your feet after taking off your shoes and socks in the car. Much as you had anticipated, there wasn't really anybody here aside from the occasional beach goer. A family was playing a short ways from the entrance, entirely focused on the toddler building sand castles to notice you. After taking a moment to slid into your bathing suit and dumping your regularly clothing by the rocks nearby with the packaging, you quickly ran to the water with the hoop in hand. The water felt cold against you skin as you swam a short ways away from the beach.
Once you were a good distance out, your eyes glanced downward at the circular opening that sat before you. Bringing the hoop above your head to swing down, a wave crashed into you to interrupt your focus. The cold water crashed on top of your, submerging you beneath the waves. In the middle of that distraction, the hoop had suddenly left your possession. A frantic look around the water showed that it was currently sinking into the bottom of the body of water. A brief glare of the silver end caught your eye just before it would be swallowed by the cloudy depths. Kicking your legs as fast as they could go, you swam after your fallen hoop before it was lost forever.
Diving deeper and deeper proved a challenge as fatigue settled in. You reached out as far as your dominant arm could go in some vain attempt to close the distance and catch your hoop. Yet the farther you sunk, the closer your fingertips were getting to the edge. You pushed onwards and reached even farther...
Until a sudden force would push you away. The current was strong enough to make any attempts at fighting against it pointless. You floundered about, tumbling in the current as the hoop was close behind you. It took some doing but you were able to gain your balance back, just in time for the hoop to go speeding towards you. It was much too fast to catch at this point, and all you could do was watch as your body went through the center.
An explosion of sensation took your body by storm. Your skin felt touched with an unknown energy, hairs standing up on end. In one moment, everything would change. Your naturally short hair lengthened to a wavy style and floated along in the water behind you. The brown color lightened to a more orange tint that was a touch more colorful than most gingers you knew. Your Adam's apple shrunk down inside of your throat as your voice become more melodic and higher in tone. The body you had trained so hard for vanished before your eyes. Pectorals swelled with tissue and flesh, becoming a noticeable pair of breasts that hung loose in the cold water. This trail of loss continued down both arms, becoming more dainty and petite. Hips flared outwards and gave you an hourglass shaped build that would catch the eye of many a suitor.
But the most drastic change of all was below the waist. Both of your legs fused together into a single limb, which upset your balance against as you fell horizontally in the water. The new singular limb grew in size as the surface would harden into the scales of a fish. Toes followed suit and fused with one another to become a thin layer of webbing at the end of your now apparent fish tail. Even a check underneath the lip of where the tail met your waist would prove that you were now female!
It was over in mere seconds as you swam befuddled. Before you had been holding your breath for that precious air, but now you could breathe underwater as if it was second nature. Even the once cold water felt perfect to you now. But the hoop had now vanished! You didn't see where it went as it passed you, and with the size of the beach, it could have been anywhere! With a head full of worry, you swam to the surface to try and get a better look. It would take some getting used to swimming with your hands only now, while you got used to your new lower half.
Once above water, the hoop didn't appear to be out of the murky area of the beach. Swimming around didn't get you anywhere either, though feeling your new supple breasts bounce with every stroke was such a new feeling. After five minutes, you'd pull yourself up to sit on an outcropping of stones, dividing the beach from private property, and open your mouth to vent your frustration.
"O' woe is I,
An afternoon's swim turned awry.
Once a kin of the inland,
With only a tail, am I bound beyond sand?"
The sudden verse caused you to cover your perfect lips in shock. That voice was beautiful, moving even. It sung to an unheard melody and was as sweet as honey. Itwould have caught your attention had you been among those listening from afar. But that's not at all what you had wanted to say. Was this some kind of trick that came alongside this body of yours? After taking a moment to collect you thoughts, you slowly lifted your hands from your lips and tried again.
"Why does my voice guide me so?
Every utterance I ask allegro?
As I can't help but serenade,
I hope not too far the hoop has strayed."
So this was going to take a while to get used to. It looked like talking was off the table for now as you couldn't help but sink every word that came out of your lovely mouth. But then, out of the corner of your eye, you spotted a man wandering over with an entranced look in his eye. You did recall something about sirens and mermaids being able to charm humans who listened to their song. Maybe he could help you in your search? The guy was handsome, a thought that normally wouldn't have affected you, but was now getting you...curious.
There was also the fact the hoop could still be out there right now, waiting for you to find it again.
After second thinking, you decided to...