Jack was one of the children that resulted from Kat's sick science experiment. He ended up in the care of some really kind folks that had a house in the country side.
He was surrounded by people going about their day like always and he was familiar with the use of horses to help plow the land and for transportation.
He was secretly practically in love with them. He liked almost anything there was to like about their species. He often took walks around the forrest and sometimes found it hard to navigate the terrain. He often wondered how hooves would faire against it.
He sometimes envied horses due to their easy lifestyles. They would just plow all day and not have to worry about anything. Nobody had any expectations of them. Just to stand on their 4 keratin hooves and to pull. He secretly wanted that in his heart and due to this one night he fell asleep while thinking of walking on all 4 with the hooves he wanted so much.
As soon as he fell asleep the seconds hand on the clock stopped for 3 seconds and glowed.
During the night his body underwent the transformation he so desired.
His spine lengthened and formed a tail which eventually got a coat of hair.
His ears migrated at the top of his head and turned into horse ears.
His legs as per requested elongated from his heals down quite a considerable amount and formed his back cannons. As they were elongating his toe and pinky fingers started to shrink and to retract into his foot, leaving his 3 medial fingers to merge and create his cannons from what the soul of his foot once was.
What remained of his feet formed his pasterns and then his hooves started sprouting from his pasterns.
His torso elongated and became more barreled. His shoulder blades were moved under him to better support his weight while simultaneously restricting his movement by quite a lot. Horses don't need much more than forward and backwards motion on their limbs and he was about to find that out once he would wake up.
His back and fore arm lengthened and became more muscular.
His wrists started to torn into the a horses carpal bones.
While his palm was elongating his outer two fingers started being absorbed into his elongating cannons while his 3 remaining palm finger bones merged together and became one big load bearing bone. Apparently horses evolved 2 out of their 3 fingers out and the remaining merged together. Jack was about to experience what it was to walk on sturdy legs that wouldn't break as easily as his flimsy human hands.
His 3 fingers fused together to create the pasterns and then his hooves.
His neck elongated a bit and also received a mane.
When he woke up he tried to lift up the blanket over him however his arms weren't set up for that motion anymore.
He started to move around and felt that his arms and legs were really heavy.
Eventually he kicked the blanked off and revealed his 4 equine legs that ended in 4 shiny black hooves.
He just stood there mesmorised on his back and looked at what he wished for.
He rolled himself out of bed and on his 4 hooves. The fact that he had lost his fingers in favor of these hooves was a restriction that was sickeningly enjoyably to him.
He managed to walk out of the house.
After 10 minutes of walking in the yard he decided to venture farther.
He went out the front gate where a few people saw him and started to gather around him.