Miley began to sing the same song she used for Julie. Derrick immediately leaned back and grunted. His sister resisted turning around because she didn’t want to risk seeing him naked. Thus, she missed it when the boy’s body began to change.
Rapidly, his young manhood slipped inside his crotch and was covered by a slit of skin. It looked an awful lot like a vagina, which scared him a bit, but he quickly realised he could make his male parts come out if he felt like it. Just a second after, a bunch of scales spread over it, hiding them from casual view. His human legs lost their bone structure and merged together, flowing out into one handsome tail which was covered in gleaming scales. Finally, his feet flattened and spread out, developing a fishy tailfin, finishing the transformation.
Miley let out a breath as she watched Derrick’s large blue eyes flutter open and go immediately down to what used to be his legs.
“W-Wow...” He mumbled, completely astonished by his new condition.
After hearing his brother's reaction, Julie couldn't resist it and immediately whirled around. She gaped at the sight of her brother, speechless.
Derrick couldn't help but laugh as he wiggled his fins. He was amazed by how flexible his lower half had become.
“Check out your mer-bro!” Miley giggled.
Derrick’s face glowed in bliss. “I-I…uh, this feels so different!”
“You're loving it!” Miley laughed. “We’d better get going. Come on, let's get out of here before anyone sees your sexy fishboy parts.” The three colourful mermaids disappeared under the surface. Right behind them, Derrick the merman worked his way into the water, trying to figure out how to move with only one bendy limb.
Then, the beach was empty, again, except for a lone, forgotten copper-hued mermaid tail lying in the sand.