Having been the subject of many paintings and photos when she was young, Rebecca knew there was an irony of herself painting after her retirement. But she actually liked painting a lot and she had enough time to hone her skills. She didn't expect any of her paintings to end up in the Chicago Art Museum, but she's been featured in a few galleries by now. It helped that she had such a good subject to paint.
Ganondorf was lucky by racehorse standards. Retirements tended to be very short, especially if leg injuries were involved. But Ganondorf was put out to pasture earlier than others. He was a very striking horse, much taller than the average racing horse with a jet black coat and a red mane and tail that were rather perplexing for a horse. He was a mixed breed, there was no doubt, with a good amount of Percheron to account for his height. However, new changes to the regulations regarding breeds and height meant Ganondorf was no longer illegible for official races. But now he could enjoy a comfy life on Rebecca's ranch with the occasional visits from Rebecca's grandkids. One of her grandsons renamed the racehorse Ganondorf because of his resemblance to the main villain from the Legend of Zelda games. (But not Ganon, that was a pig's name.) It was certainly better than 'Sunset at Night' like he used to be called.
It was on that fateful day that Rebecca was painting another picture of Ganondorf. The horse was being very patient as he was standing in the midday sun with a lead rope keeping him by the fence. Rebecca had gotten the basic shapes in the painting down, now she had to do the details.
Rebecca wiped her forehead with her sleeve and said, "Scorching, isn't it?" The stallion gave a low knicker. "Ok, you've been standing there long enough," said Rebecca, "Let's break for lunch and we can start again when it's less hot." She walked over and untied Ganondorf from the fence. The horse gratefully walked with Rebecca as she topped up the water troth and put some hay out. "Now, I'm going to cool myself down. See you later," said Rebecca. She was going to give Ganondorf a kiss on the nose, but he moved his head a bit and she ended giving him a kiss on the lips. Rebecca spluttered a bit before saying, "I'm not sure I like you that much." She headed back to the house as the horse stared drinking.
First thing Rebecca did was go to the sink to pour herself a glass of water. She needed to get the taste of horse lips out of her mouth. As she swished the water around her mouth, she was aware that the water had a strange tang to it. She spat out the water into the sink and said, "Something's wrong with the water. I hope it isn't contaminated with mercury or something." Then Rebecca thought back to the water she just added to the troth. "Oh, I think I better pour that out before he gets sick," she said before heading back out.
When she got towards the barn, she could hear some deep moaning, which made Rebecca worry. But as she got closer, it sounded less like a horse with stomach pains than a man who was enjoying himself. "Ganondorf, you ok, boy?" called Rebecca.
"Never felt better," replied a male voice.
"Oh, good. I was worried the water-" started Rebecca before pausing. "Who am I talking to?" she asked.
"Me," said the voice as something stepped around the side of the barn. Rebecca wasn't sure if she was suffering from dehydration-based hallucinations or not. Because the tall, muscular horse-man looked very real. His coat and hair was the same color as Ganondorf's and Rebecca couldn't help but notice the impressive stallionhood that was halfway out of its sheath. There was also a rich, musky scent in the air and Rebecca didn't think she could hallucinating that.
"Ganondorf? What happened to you?" asked Rebecca.
"I'm not sure, but I don't think I could be happier," said Ganondorf, "That is, if you're happy with me."
"What?" asked Rebecca as Ganondorf walked up to her.
"That little kiss earlier wasn't a complete accident," said Ganondorf, "I really did like you as a horse, but I think I know what true love is now. And I want to give you a proper kiss now." With that, he leaned his head down and gave Rebecca a much more meaningful kiss on the lips.
Rebecca was shocked, but she wasn't pulling away. There was something about Ganondorf that lit a fire that hasn't warmed her in many years. The taste of him wasn't unpleasant, not worse than some of the men she's kissed, like her late husband. But she was feeling strange. It felt like her face was pushing into Ganondorf's. Pushing the stallion back, she could see that her face was growing out, her nose and mouth stretching into a muzzle.
Soon after that came the need to take off her shoes. As Rebecca worked at getting them off, she could see her hands were growing white hair and her nails were getting thicker. When her shoes and socks were off, she could see her toes were merging into one hoof, but she didn't have trouble standing. Feeling behind her, Rebecca could feel something pushing out of her spine. She undid her pants and lowered them to allow her new tail to grow out. She felt her head, feeling her ears grow out and her face finishing becoming a muzzle. She didn't need a mirror to tell she's some how became a humanoid white mare.
"Are you ok?" asked Ganondorf with concern, though his penis was emerging more from its sheath. Rebecca's nostrils could smell the sexual attraction he was feeling and she was starting to feel it herself.
"I think we need to go somewhere more private," said Rebecca as she walked into the barn, allowing her pants to fall on the way.
Ganondorf wasn't about to say 'no' and he quickly followed Rebecca, his cock fully emerging and ready to go. He nibbled a bit at Rebecca's neck before helping her remove her ill-fitting shirt and underwear. Rebecca pushed the stallion onto a hay bale before climbing onto his lap. She grabbed Ganondorf's shaft and rubbed it as she aimed between her legs. The woman she was before would have hesitated before putting that gargantuan pillar inside of her. But the mare she was now plunged herself down with gusto.
The two horses snorted and nickered as they proceeded to mate. Rebecca felt an odd thrill in doing this, like energy was building up inside of her that was different from usual sex. From Ganondorf's perspective, he could see the changes happening. The worn, wrinkled skin was tightening up as the veins became less prominent. Her muscles became toned before growing, giving her more strength. Her flabby breasts were becoming bigger and rounder, rising higher up on her chest. Putting his mouth to one, Ganondorf tasted fresh milk flowing out. Rebecca moaned, her voice sounding stronger as the last of her old age faded away. She was still a pure-white mare, but she was a young, strong mare. She kept riding Ganondorf with her renewed vigor, pushing the stallion to the edge. Then with a loud whinny, they both came, Ganondorf shooting heavy loads of seed into Rebecca.
Some time later, Rebecca and Ganondorf were examining the incomplete painting. "Not sure if I can do more details now," said Rebecca, "I suppose I'll have to use a different style to finish it."
"It'll still look great," said Ganondorf, "And you can paint more pictures of me now. I can do better posing now."
"You definitely can," said Rebecca with a lusty purr, "Maybe I should do some nude portraits."
"Maybe you should be the one in those portraits," said Ganondorf coyly.
"You paint?" asked Rebecca a bit skeptically.
"Well, how hard could it be?" asked Ganondorf.
Rebecca chuckled and said, "Oh, you've got a lot to learn. I'll need to teach you so much about art."
"Anything else you can teach me?" asked Ganondorf, still feeling lusty.
Rebecca licked her thicker lips and said, "Oh, so much more."