By now, the sensation of her body starting to undergo physical changes was becoming quite familiar to Mary, so much so that she almost found it comforting when the warm and stretchy sensation began to wash over her. Held tight by Karima beneath the water, her head nestled among the indian woman's quartet of enormous breasts, she was at total ease, completely unafraid of her body changing further - if anything, she welcomed it, eager to further immerse herself in the comfort that accompanied her roommate-turned-lover's presence. That she was becoming cattle didn't even bother her - after all, Karima was happy with it, so why be afraid herself?
It started washing through her hair, the change visible as strands wafted into her view, their coloration changing from root to tip in a rapid transition to a jet black color. Her free hand toyed with several strands, before gliding down to massage at her scales as she felt something ripple across them. Their own color shifted too, becoming stark black - curiously, though, she glanced down to find no splotches of white as was found on Karima, just the solid black color from her hips to her tailfin. Enamored with this oddity, she took little note of Karima shifting her around so that she floated with her back to the mercow's chest, hands holding tight to Mary's breasts.
These initial changes had been cosmetic, but with a new wave of pleasure over her body, they started to become more substantial. Right before Mary's eyes, she watched her arms and torso begin to thicken, not with fate, but with muscle - a new feeling of power flooded her mind as her physique rapidly bame extremely well-toned, with fantastic definition to her muscles, not unlike how Karima had been before her transformation. She laughed with glee at rubbing her stomach to find a six-pack; where once had been a bit of flab there was now thick and corded muscle, pure power that was hers to command. Her delighted laughing only slowed as a new weight appeared on her face, in the form of a gold nose ring hanging from her nostrils, followed shortly by two coral horns, shorter and thicker than Karima’s, emerging from her temples.
As she felt up all this new raw power, the transformative energy rebounded down from her face, back to the point where her toned abs transitioned to her beautiful and powerful tail. Briefly, she was confused as she felt her womanhood closing up, sealing suddenly - and then, excitement, as something began to extend out. What had once been her clit was growing out, longer and longer, gaining shape and definition as a sack swelled up beneath it. Two heavy endowments hardened within that sack as a whole new appendage shaped itself - a long, thick cock, easily over a foot in length, girthy to match, with two balls filled with seed swinging beneath it. She had never once even imagined having one, but now that it hung from her, now that she gripped it and gently rubbed, it felt so very right, so perfect an addition to her body.
"A herd needs a bull," Karima elaborated sweetly as she squeezed both of Mary's nipples. Thankfully, she had retained her immense bust, but what squirted out of the large sacs was much goopier, much saltier, than the bounty of her cowlike lover. Her tits jiggled not with milk, but with cum, an enormous resovoir of fertility - she could feel it was connected to her new shaft, able to be released the traditional way, but it could just as easily be drained out through her nipples. She had no doubt, as well, that it was just as transformative as her prior milk, perpahs even more potent in that regard - one good burst would surely be enough to turn any woman into a plush mercow like Karima.
And she had far, far more than one release available, given the enormous volume within her breasts and heavy ballsack. "We'll have a herd," she moaned out, "A huge one." Her new member was already erect just considering how many could be converted by all the cum and milk the two of them had, permanently transformed into cattle of the sea. She, too, was stuck like this, her ability to regain her legs now vanished - but for the sheer erotic thrill now rampaging through her, Mary considered it a worthwhile sacrifice. All that stood in her way now was indecision - did they seek out other mermaids to turn into mercows? Did they travel to the nearby beach, and make the human women into the first elements of their herd? Or did she ravage Karima right here and now, breed her brains out, and start a herd the old fashioned way?