The changes begin slowly at first. Bones and muscles shifting, lengthening and rearranging, just as your own change into a unicorn mare had begun. Then, as thick brown fur erupts across his body, the changes speed up rapidly. His hands and toes turn black and fuse together. His face ripples and shifts, lengthening into a snout, and little curved horns grow above floppy ears.
“Stop, please!” calls one of the captives.
“Stop? But he’s enjoying it so much!” you say. “Just look at how his hard cock strains against the laces of his pants!”
It’s true. The man’s pants are sporting an impressive tent, but that’s not particularly surprising. You made sure he’d enjoy every single second of transformation when you cast your spell. The man lets out a long groan as his legs start to swell, splitting the legs of his pants. His boots are tatters of leather.
His back suddenly arches, and you are forced to pull your fingers from his chest as he falls to all fours. You can see his spine lengthening beneath his taut shirt, as his head and neck align with his new posture.
“This is what awaits any that defy my rule over this domain,” you say to the captives, gesturing towards your victim, who was now more animal than man.
The man’s chest barrels outwards, shredding his shirt and thick pink tubes descend from his stomach before ballooning into large, dangling udders that swell with milk. His pants follow right after, freeing his big dick and dangling balls at last, as his ass and hips crack and grow into the large, distinct rear of a bovine. A tufted tail sprouts from above his puckered asshole.
Strutting around to his ass, you reach down and give his balls a good squeeze, enjoying the feel of the big hairy sack in your hand. Your touch is too much for him though and pushes him over the edge. He bellows and, rearing on his back legs, sprays ropes of thick white cum over his fellow captives before his dick and balls are sucked into his body with a wet slurp and transform into a wet, winking cow cunt.
Where before had been a defiant human man, now stood a horny heifer desperate for a big bull cock to breed her.
“Your friend is still in there,” you tell the captives as they try to wipe the cum from themselves while still bound in vines. “His mind is now that of a heifer in heat, unable to deny herself to any bull that approaches, but he is still in there. Completely aware, and unable to stop herself from wanting nothing but a big hung bull on her back.”
You punctuate your speech with a slap on the heifer’s rump that elicits a startled moo from the transformed creature and another cry from the captives.
“Anyone else wants to question my claim?”