Baxter slid down a ramp and splashed heavily into the water. The other subject fell out of a parallel ramp. They were in a large lagoon-like structure that went on and on, with waterfalls, coves and (other) aquatic life.
Baxter closed his eyes as he splashed into the water, and instinctively began struggling and trying to kick his legs and paddle with his arms.. But he had no legs...and he couldn't breathe!! Gasping, he relaxed and let his new lungs began to do their work. As he gradually gained control of himself, he took stock of the situation. This was his first opportunity to stop and get a grip. He looked down: just above his old pubic region, sheets of scales snaked down a sinewy flowing tail that could not possibly be hiding legs or knees underneath, ending in a large, five-foot wide shiny plummaged fin. A small mound near the base of his tail where his hips used to be marked the new residence of his equipment. His chest seemed to have tightened up, and his remaining skin now had a tint of blue to it. He couldn't see his face, but he could tell his hair was now considerably longer, was blueish green, and haloed around his head. In his new legless form, he quickly found he could easily suspend himself in the water and move about.
Baxter still didn't know what to make of his aquatic partner. He/she was a sight to behold, her long billowing red hair beautifully contrasted with her orange and red fin and tail. Her breasts , while not too large, seemed to defy gravity in the water. As their eyes met, his pace quickened. What should he do? "Should I try and talk to my fellow prisoner/transformee? I mean, I know I just had a pretty traumatic experience, but this guy may not be OK with suddenly changing genders on top of that!" As he considered this, the new mermaid spoke...