Tom shut his eyes tight, much to Kate's delight. He didn't open them again until Matt spied a small wiggling at the rear of his pj pants.
"What did you do, Tom?" Matt asked, seeing the wiggling starting to puff our into something more.
Feeling the pluming of his tail against his sore ass, Tom answered first with a moan. A tight sensation pulled his testicles up his body, shriveling the skin before the teasing of air against a newly opened slit just below made Tom bite his lip. Added to this the darkening of his nose and sudden loss of two inches in height, it was clear to Kate and Matt that Tom was already on his way out of humanity.
"That's it. Smaller makes it easier to shoo you off into the forest," Kate teased, reaching out to Tom who was now nearer to her height and his features, though still mostly human, had become more feminine.
Suddenly, Tom's pants, loosen by a reduction in height and width, dropped around his ankles and despite bending over to snatch them, his underwear followed. Sensing the eyes on him, Tom felt his body tense and instinct took over, lifting his tail before spraying a pungent odor that, coupled with the growing snout and blackened hair with white stripe, gave little question as to Tom's fate.
"Gross!" Kate said dismissively, covering her nose with her sleeve while Matt still couldn't believe what was happening before his very eyes to his roommate. It was then he saw, under the now pluming skunk's tail, Tom's new sex was ripe among the shiny new black fur of his ass.
When Tom looked back, blushing and taking off his glasses, he saw the bulge in Matt's pants and white hairs starting to stick up through the top of his head. It made Tom look to his hands, which were far more slender and bestial, with pads forming and nails taking on a new shade. With some struggle, he managed to get his shirt off, revealing a body sweating and sprouting fur all over. Rows of teats bounced as Tom fell to all fours, wincing for a moment before looking up.
Everything in the room was getting so big. This was really happening. Looking back, Matt was just starting to realize what was happening to him. Fur was sprouting down his arm while after a brief struggle with his pants, a tail popped out the back and quickly started taking on a skunk's pattern as well.
Matt then looked to his own loins and felt some relief, though the sight of his cock, now redder and misshapen, pulling into his sheath was odd. Getting to fondle a set of furry testicles soon caused the new skunk cock to emerge.
"F-fuck me, Matt," Tom said in a willowy thin voice that ended in a growl as his muzzle took it's final shape.
Kate, troubled by the smell that had likely soaked into her very skin, was at least getting to watch these two devolve quickly into the animals they were. It was a sudden dizziness and then reaching for and missing the nearby desk that alerted her senses that something was wrong. That's when she started to notice things.
Her nails were darker and clothes looser. Picking at them, she was also startled to see her arm hair darker. Then came the sharp pain at the base of her spine. Feeling at her ears, she had hoped to fine them round but instead,
"Oh no. No, no, no, no!" Kate said in a growing panic. She went to run but her already shrunken feet stumbled easily in her larger sneakers. Kate dropped to her knees as a cracking sensation from the base of her skull, down her spine, and through her pelvis and hips forced her permanently onto all fours. "Noooooo!" Kate cried, looking back to see her own skunk's tail taking shape.
Meanwhile, Matt's new snout had found Tom's new gender and caused the last of Tom's fur to come in fully, leaving him a mostly complete skunk. It was when Matt mounted and found his mark that Tom gave himself in to and became just another skunk, soon to be bred.
Kate could only watch and weep as the two roommates consummated their new lives with skunk chitters as the two finished both their transformations, but their coupling. When Matt came loping over to her, Kate was desperately trying to keep her thoughts together and think how to reverse the effects of the skunk spray. Then Matt was on her and it didn't matter.
By the time Matt planted his seed a second time, any semblance of Kate was washed away and was just as animal as the two she had cursed. When they were all eventually shooed out, a happy male skunk followed by two already pregnant looking females, with the fate of the students left a rather pungent mystery.