(P.S. This part of the story (?) is told in second person (you) , but you are free to continue in first (I, me etc.) or third person (him, he etc.) just by scolling down and TYPE a story of your own under The Next Part of The Story: [insert story here]! ENJOY!)
A mermaid of course! As soon you click "submit", you fell that something's wrong. First thing you noticed was your now waistlong blonde hair. Still aroused, it began to tingle in your breasts. Strange enough, they seemed to grow while you caressed your nipples. You felt a pulling sensation at your spine, as a numb formed and started to grow slowly. Now noticing the changes, you stopped touching yourself. Looking down your body, you saw that your breasts had grown to c-cup size. Between your legs you saw your growing tail. You touched it and it felt so good. Warm and alive. The skin felt like it was covered with thousands of bumps. The tail continued growing, and soon you discovered that those bumbs were scales. Your legs felt weak and you noticed that they had become thinner. You laid down in the floor. As the tail grew and grew the scales changed their colour from skin to a silvery blue. Your legs began to retreat into her hips, her feet forming pelvic fins. The tail got thicker, your penis became a Vagina, as it and the asshole moving down to the fins. You flexed her tail as it grew almost two meters long. The end of the tail formed a beautiful fluke. The scales grew all over your tail, covering it in silverblue. You moved your now webbed fingers down to your new vagina. Nearing its end, the change urged you to masturbate, caressing your scaly skin, fondling your new breasts. A dorsal fin grew, starting at your waist and the tail almost down to the fluke. Reaching your orgasm, you could no longer braethe air. Three slits opened on your ribcage, housing your newly formed gills. A second later, you was teleported to your pool where you can live, but what to do now?