The mountain lioness approached the stream with an easy gait. She was an apex predator, there were few animals who'd dare to challenge her. Wolves and bears could be a problem, but she had lived long enough to be aware of other threats to her. She had born and raised several cubs and they've all left by now. She was 6 years old by now, a quite respectable age for a cougar. She probably had a few more years left in her, perhaps it was time to find another mate. But right now, she was quite thirsty.
The puma lapped at the water in the stream. The cool water slacked her thirst, but she was aware of a strange taste to it. The taste wasn't intolerable just...out of place. But that didn't stop her from drinking it. After a minute, she had drank enough water and walked away from the stream. The puma hadn't gone far when she started feeling numb throughout her whole body. Her legs wobbled a bit as she walk and her head started to swim. The cougar managed to keep her balance long enough for her to fall into a patch of tall grass. What was going on? Why did she feel so dizzy?
The numbness in her body made it so that the puma could only vaguely feel her body changing. Her torso extended in length slightly before its shape started to change. Its barrel shape was flattening out into something broader. Her shoulders clicked as they pushed outwards. Her front legs lengthened a bit as her front paws went through a dizzying change. Toes stretched out, becoming more dexterous in shape. Her dewclaws slid downwards before they extended out on top of newly-formed digits. Meanwhile, her back legs were also extending, but mostly they were thickening with more muscle so they would be able to support her body by themselves. With two pops, her hips dislocated before they locked into a new position, one that favored a more biped position. The puma's muscles hummed before they started becoming larger and more pronounced. Her backside quivered before it began inflating with excess fat. Her teats had all disappeared saved for two which had been traveling northwards. Once they were aligned with the puma's pectorals, they swelled in size before her pectorals started ballooning out from under them.
The cougar panted as these changes ravaged her body. But then she felt the tingling intensify through her head. She squeezed her eyes shut as she felt her brain pounding. No, not just pounding, expanding. She could feel her grey matter altering and filling more of her skull cavity as more room was given to it. Her head was restructuring, her face altering so that it would be more capable of expressions. Then a series of images seemed to flash before the cougar's eyes as her understanding became a lot more profound. She opened her eyes and looked down at herself. New words were springing into her vocabulary: hands, thumbs, arms, ass, breasts.
The cougar examined her new hands with fascination. There was still fur on them and pads on her palms and under her fingers plus her retractable claws being present instead of fingernails, but otherwise they resembled a human's hands almost exactly. Her attention then turned to the large mounds mounted on her chest. Her breasts were large and rounded, though they were closer to dewdrops in shape than honeydews. With some caution, she felt her new breasts with her new hands. The cougar soon let out a moan when her fingers felt her nipples. They were more sensitive than she would have thought. She continued to massage them, letting out moans and mews of pleasure as she did so. Eventually, she became aware of a wetness on her fingers. She lifted one hand to her face and saw white drops on it. She sniffed and licked her palm, a little surprised to be tasting milk. A glance down at her nipples both were leaking a few drops. Well, this was unexpected, but not unpleasant.
The cougar moaned even more as she massaged her breasts, allowing more milk to leak out. Then she felt a build-up of pleasure in her pussy. She needed something inside her. And since there weren't any male mountain lions around, she'll just have to take care of it herself. Fortunately, her new fingers were up to the task. She slid one hand down and circled her pussy. She moaned as she felt the wetness of her lips before she inserted her fingers. The cougar fingered herself quite vigorously as her other hand work on her breasts. She panted as she felt the pleasure building up. Her fingers moved at a rapid place to stimulate her erogenous regions. Just a little further...so close...the cougar let out an orgasmic cry as her pussy let out a splurt of fluid. Her breasts gave small jets of milk as well.
The cougar panted a bit before she started licking her hands off. Her milk and juice tasted so good. When she was done, she slowly got to her feet. She was a little dizzy at first, not just from the rush of blood but also from standing taller than ever before. Once her balance was set, she walked over to the stream. She found it rather easy to walk on two legs. When the cougar looked in the stream, she saw what could only be described as a mountain of mountain lioness. Perhaps 'mountain' might be a bit strong, but she was very well-built. Her years of experienced muscle translated into a sold amazonian build. That wasn't to say she wasn't feminine. Her breasts were sizable and didn't look out of place on her muscular body and her hips had expanded out to proper child-bearing width. She glanced at her backside and saw that it was plump as well, though perhaps slightly on the saggy side.
The cougar flexed her muscles, pleased with her new physique. But still, she wasn't satisfied. Her old mating instinct was quite active now. But she was less interested now in mating for reproduction's sake, she wanted to mate for the sake of mating. Her new hands did a good job in stimulating her, but she wanted an actual penis inside her. Well, even if she was an anthro, she was still a huntress. Finding someone to mate with shouldn't be a problem.