You lay under the shade of the oak tree, feeling the coolness of the ground against your back. The gentle breeze rustles the leaves above you, creating a soothing melody that lulls you into a state of relaxation. Harry, the black stallion, stands nearby, his dark eyes watching you with an intensity you don't quite notice.
As you drift into a light sleep, a strange sensation washes over you. It starts at your feet, which begin to itch and tingle. You wiggle your toes, trying to shake off the sensation, but it only grows stronger. Your shoes feel tight and uncomfortable, as if they’re shrinking. You sit up and pull off your shoes and socks, sighing in relief.
But the relief is short-lived. The itching spreads up your legs, which start to feel tight and cramped. You glance down and gasp as you see the muscles in your legs bulging, your calves thickening, and your feet elongating. Your toenails darken and thicken, merging together to form solid hooves. Panic sets in as you realize what’s happening, but your body refuses to obey your commands to stand or run.
Your legs continue to change, becoming sturdy and muscular. The skin darkens, a smooth coat of glossy black hair sprouting and covering them entirely. The changes move up your thighs, which become thicker and more powerful. You feel your pelvis shift, your hips widening and realigning to accommodate a quadrupedal stance.
Your spine tingles and elongates, and you instinctively roll onto your hands and knees. Your fingers dig into the dirt, nails transforming into hooves similar to your feet. Your arms bulk up, muscles rippling beneath your skin, which is soon covered by the same sleek, black coat. Your chest broadens and your shoulders widen, shifting to support your new form.
The tingling sensation spreads to your face, which begins to stretch forward into a muzzle. Your nose flattens and broadens, nostrils flaring. Your eyes grow larger and move to the sides of your head, your field of vision expanding. You feel your ears stretching and moving upward, becoming long and pointed, covered in short black fur. They twitch and swivel, picking up sounds with newfound sensitivity.
A pressure builds at the base of your spine, and with a sharp, sudden pain, a tail bursts forth. It grows rapidly, a long, flowing tail covered in black hair. You instinctively swish it back and forth, feeling it move naturally.
Your human male privates begin to shift and alter, the skin darkening and growing thicker. The transformation is slow and deliberate, your penis lengthening and thickening, changing shape to match that of a stallion. Your testicles enlarge and change position, adapting to your new quadrupedal stance. The sensation is a mix of discomfort and a strange, alien awareness as your reproductive organs take on their new form.
Your mind reels with the intensity of these changes, the unfamiliar weight and size of your new genitals becoming an integral part of your new equine body. The fur grows over the skin around your groin, seamlessly blending with the rest of your glossy black coat.
Your mind feels fuzzy, your thoughts becoming simpler, more instinctual. The human part of you fades as the transformation completes, leaving you as an exact copy of Harry. You stand on four powerful legs, muscles rippling beneath your glossy coat. You shake your head, your mane flying, and you whinny, the sound echoing through the forest.
Harry, the original stallion, watches you with approval. He approaches, nuzzling you gently, and you respond in kind, understanding his silent communication. The two of you stand together in the clearing, the bond between you growing stronger as you accept your new identity.
The hours pass as you explore the forest with Harry, your senses alive with the sights, sounds, and smells of nature. As the sun begins to set, you remember the attendant's words about returning before nightfall. You nudge Harry, and together, you make your way back to the stables, where your journey began.