Mary looked at the vials, trying to decide which one to pick. Then a new drawer pops open. In it is a single vial marked with a picture of a woman. However, there is something strange about the woman on the vial. Mary takes a closer look to discover that woman had not legs, but a fish tail. Recognising that this is a mermaid, Mary giggles in childish glee. Having been a mermaid lover as a child, and then through the years, she had always wanted to be one. Mary knew that the vials would turn whoever drunk a vial would turn into whatever was depicted on it, so she read the vial first. "WARNING - This vial only goes works for a woman. This vial causes the woman who drinks it to become a mermaid. The serum genetically alters your DNA to make it your normal form. Thus, you will spend most of your time as a mermaid. You will undergo many changes, which include hair colour change and etc. You will be able to switch between human and mermaid form. However, this will take a bit of energy and you will only be able to do it a few times a day. the transformation will take place automatically if you touch salt water with anywhere but your mouth. The serum may also cause your breasts to lactate, this being a uncommon occurrence, but there never the less."
Mary grinned, and with that, uncorked the vial and then placed it back in the drawer. for a few heart stopping moments nothing happened. Then a burning pain flourished in her legs, causing her to fall over. He clothes disappeared, leaving her nude as she fell to the ground. She sat up, but when she tried to stand, she found that they were unresponsive. relaxing, she attributed this to the changes beginning. And beginning they were. Between her stiff legs, skin began to grow between them, in essence fusing them into one long limb. Then her feet themselves were pushed outward, until they were jutting out from the sides of her enormous limb. Pain rushed through Mary's legs as she sat, unable to scream or even speak. Then her feet slimmed, growing thinner and thinner until finally stopping, having morphed into a thin, almost transparent fin. The silvery scales began to grow and spread up her fused legs, making them shiny. Unbeknownst to her, her facial features changed. Her hair grew past her shoulders, flowing to the center of her back and a wave of colour ran down it, turning it from brown to blonde. Her eyes changed to a sea blue.
All the while, the scales continued to move up her fused legs, but the scales stopped at her waist. Her pussy was till there but hidden under a scaly piece of skin. But the changes weren't over yet. Her breasts began to swell, growing from mere handfuls to FF cups, her nipples growing to the size of her pinky joint. Her areola spread, making a circle with a radius of 2 and a half cm from her nipples to the edge of her areola. Then something happened. her breasts grew heavier and her nipples darkened and began to drip milk. MILK? The vial had said that it was possible, but unlikely. Apparently her cells had been different, causing this mutation. Then to complete the transformation, seashells appeared coving her nipples, and somehow they stuck. Apparently they were there for the purpose of hiding her nipples, however they did a poor job, with her areola visible around the shell.
Mary sat for a moment, then pinched herself to make sure she was awake. She was. She moved her tail up and down, feeling its weight. She felt something brush her bare back and touched her hair before putting it over her shoulder. It was a beautiful blonde. She tried to move, however it was pretty hard, due to not having legs anymore. But she made it to her desk, able to rest against it. Suddenly a sound was heard, and Mary found a swirling portal under the desk. It appeared to lead to a cove of some kind. Mary decided that this was a good time to try the switching of forms. So she closed her eyes and wished to be in human form. Mary felt strange as her tail separated, turning back into legs. Her breasts remained the same shape, but her seashell bra was replaced by a nursing bra, and Mary took this as a sign that she was still lactating. By this stage, her legs were back to normal and Mary found herself in her clothes, the ones which she had been wearing before the transformation. However, the clothes had been altered, so that her breasts would be able to fit.
Mary knelt down and cautiously enter the portal, which ended on a secluded cave. Sunlight shone through a hole in the ceiling. Waves splashed against the rocks, and Mary immediately knew this was the sea. Taking a running start, she dived into the sea. as soon as she touched the water, she felt her clothes vanish, and for a moment, she was nude in the water, with only the nursing bra, yet somehow staying afloat. Then she felt her legs bind together. Her feet turned to jut outward, and flattened, becoming the transparent fin. Mary looked down as the scales engulfed the long fused legs. Finally, her nursing bra disappeared, replaced by the seashells.
Now swimming in the cove, Mary giggled, as she watched in amazement at how she managed to stay afloat with ease. The she dove. Feeling the water rush into her lungs, she panicked, before letting the water into her lungs. Immediately, she relaxed. She was able to breathe the water as easily as the air. She was also able to see in the water, seeing in it as clearly as in the open. She continued to dive, going a few feet deeper until finding a hole in the wall of the cove. she swam though and surfaced, finding herself facing a beach. She was very far out, too far out for any person to swim, but she could still see the people, laughing and playing with balls.
Mary swam around for a while, until she became aware of a wetness in her breasts. She dived down, and re-entered the cove, which she had deduced to be underground. Surfacing, she sat on a ledge of rock jutting in the water and removed the seashells. She had completely forgotten that she had begun lactating due to the vial. Her breasts were leaking, white droplets of milk dripping into the sea, and becoming diluted with sea water. She squeezed her nipples, sending milk spraying across the water. Mary moaned, feeling bolts of heat race down to her hidden, submerged pussy. Mary, paused, not knowing what to do. She needed to empty her breasts. So she brought her right nipple to her mouth and began to suck. Milk trickled into her mouth, tasting creamy and delicious. Her other hand reached down past the strip of skin and began to finger her pussy. Mary moaned, feeling her pleasure grow and grow until finally, she came. Liquid pooled around her fingers, and milk shot involuntarily from her left breast, spraying drops of white across the calm ocean water. Soon she died down, with her breasts emptied and her belly full. It had been her first orgasm after being changed into a mermaid.
Exhausted, Mary hauled her tail up onto the shore and wished to return to human form. Mary didn't even notice as her tail split and returned to normal. The seashell bra was replaced with the nursing bra and her clothes reappeared, not even damp. With that, she went back through the portal and back to her room, where she collapsed, dead tired from her day.