Anthony frowned at the weird collection of leather straps and buckles inside the box. "What the fuck is this stuff?" Lifting it out, he let the straps unfold and hang loose. "This has to be some kind of weird joke. Initiation of the new guys, right?" He looked around, but could see no one else. The harness was way too big for him, and sure wouldn't provide any kind of modesty. Well, he'd chosen to go skinny dipping while the rest of the guys freaked about being naked. Anthony didn't mind showing off his body. He worked out and looked good, and his package wasn't anything to be ashamed of, either. If they wanted him to walk around in leather straps, that was fine with him. But he needed a way smaller set.
The shoulder straps were easy to identify, and he shook the harness out so he could get his head between them. The innermost straps were just barely on his shoulders, and when he had his arms and legs through what he guessed were appropriate openings, he looked more like a bird in a leather cage than anything else. There were buckles on most of the straps, but he couldn't begin to take up enough slack to make this thing fit. Still, he could shuffle carefully and make a show of wearing it to the barn. Whoever was setting this up was expecting anger, or shame, or frustration. Fuck that! He held his head high and started for the stable with a grin.
However, he had to frown after a few steps - the harness was suddenly a lot heavier, and he looked down to see that the leather and buckles appeared to have thickened. Instead of a flimsy costume, it now looked like a heavy, well-worn harness a work animal would wear. Anthony felt confused. No way this would have fit in the box, but it was what he had put on. A few more steps, though, and it didn't feel so heavy. That was weird. He continued towards the barn, finding that the harness not only felt lighter, but seemed to fit better.
Anthony was halfway to the building when he realized the harness was no longer dragging the ground. He looked down, puzzled, and then stopped with a gasp. The leather straps were still hanging loose, but they now covered much thicker, black-furred legs that ended in thick brown lumps partially covered by a curtain of long white hairs. His chest was barreled out, and black fur covered it as well as his arms. Even as he examined himself, the straps got a little less loose. But it wasn't the straps shrinking. He could see the ground moving away as he got taller, and the lumps at the ends of his legs spread out into dinner-plate-sized hooves. Horse's hooves.
Anthony gave a whinny of surprise, then grabbed his mouth with numb fingers. The sound was not human, but then, neither was his face. He could see it protruding between his eyes, even his vision getting weird as his peripheral view expanded. Moving his hands away, he realized they were also becoming lumps. Hooves. Looking back down, he felt at least some satisfaction in seeing the sexual equipment of a draft horse stallion.
What now? He was becoming an animal, sorta like the Clydesdales in the beer commercials. Anthony should probably be freaking, screaming and panicking and running around. But that wouldn't help anything. Besides, he was having trouble balancing - trying to run would put him on his face - his muzzle. Although he was scared, Anthony was also curious and even a little excited. Instead of fighting, he leaned forward and let his arms hang down. They were already more forelegs than human arms anyway, and it was easy to settle onto all fours. His neck lengthened so that he could bring his head up, and he shook himself to settle the straps as he grew into them.
Anthony knew when it was done. Not because of any change of sensations, but because he felt comfortable and normal. A sense of contentment settled over him. He knew he had been human, remembered his past, but now he was a horse and his mind accepted that totally. The straps not only felt normal, he discovered memories of being hooked to wagons and plows and how to pull them. A human came out of the barn and whistled for him to come. Anthony ambled to the man and nuzzled him, getting a chin rub and a sugar cube in reward.
"You're a smart one, aren't you?' The man chuckled and patted Anthony's neck. "You'll enjoy your stay here. Who knows? Maybe you'll want to stay." He shook his head. "Too bad your buddies weren't so accepting. They are going to be pretty unhappy." He started intot he barn. "Come on, then. We'll get you in your stall and feed you up."