Cursed Pony Book

Heath had been researching disappearances that had been happening.  All clues led him to a certain library where rumor had it that there was a book that would curse and transport people to a different reality.  Of course, he knew that this was all bull, but had to follow up the lead if he was to find any more clues.  

While there, he couldn't help but feel compelled toward a certain book in a section in the back of the building.  He took the book out and observed that it had an almost unnatural look to it, with a horseshoe clad in jewels on the cover.

Upon opening the book, a sort of force pushed him to the ground.  His surroundings began to take on a pinkish hue as his reality began to melt around him, being replaced by a more colorful, almost animated one.  Looking to where the book fell, he watched as purple smoke began to rise from it, and within it, he saw a cartoon pony looking at him with an evil expression.  He thought that the pony looked familiar, but couldn't quite place it.  It was from one of those kid's cartoons, wasn't it?

He then watched in horror as his clothes also disappeared, and he felt an almost burning sensation on either side of his hips.  Upon inspection, he watched as a light purple star symbol began to appear with small white ones surrounding it.  

Then a light purple fur began to sprout from it and quickly spread all over his body, as his hair began to change into various shades of purple and pink as bangs grew into his vision and he felt more of it grow down his back.

He then felt an ache as his spine began to stretch out from his body adorned by the same shades and colors that his hair had become began to sprout from the protrusion.  

"Am I turning into a purple horse!?" He thought to himself, and as if to confirm his suspicions, he felt as his hands and feet began to cramp and watched as they were taken over by what he knew to be hooves.  

Just then, he felt his manhood begin to twitch and tremble as it began shrink and invert into his body, and two orbs formed just above it to form her new teats.

As he did, he could feel his face begin to push out into a proto-horse muzzle and a horn grew out of his forehead.

After his transformation had ended, he looked at himself and his surroundings.  He couldn't believe what had happened and wondered if all the missing people had suffered a similar fate.  

Though, he wouldn't be thinking these thoughts for long as he felt a new personality begin to take over.  Purple washed over his mind, and Heath no longer had any memories from his previous life, and instead, she knew she had always been a pony named Twilight Sparkle.