Jeff looked at all of the options. He had always wanted body hair, but only being in his teens, he still hadn't had a lot of chances to grow some. He decided to select 30, which was the highest level of hairiness. He set the duration for 5 minutes; he thought that 5 minutes would be a reasonable amount of time for him to observe all the hair grow on his body. He felt butterflies in his stomach as he clicked "confirm".
Jeff felt his body start to tingle, and he rushed over to the large mirror in his room to observe the changes. He quickly shucked off all of his clothes and looked at his naked body, showing off the only hair on his body, his small wispy bush above his cock. Just as the tingling was heating up, the chronivac loudly beeped; "SUBJECT JEFF: HAIRINESS LEVEL INCOMPATABLE WITH CURRENT SPECIES. SUBJECT JEFF SPECIES CHANGE: HUMAN TO NEANDERTHAL.
What? What did that just say? He felt his feet tingling and feel funny. He felt a stretching and pulling sensation. He looked down and saw his feet growing bigger! His toes were stretching longer and longer, stretching across the cool tile. His feet were getting wider too. He was already past a size 11, 12, 13?! They weren't stopping either. They ached and popped as they rapidly grew. Jeff groaned from the sensation. His feet began to itch as thick brown hairs squirmed their way out of his skin. The tops of his feet rapidly became covered in a tangle of brown hairs, as did the knuckles on all of his toes. They were so hairy and big, they looked like gorilla feet! His toenails cracked, became dirty and stained, and grew wildly. Likewise, his feet began to produce a nasty odor and they reeked! It looked like his feet had never been cleaned or washed. Jeff gulped; that was probably true if these were truly a caveman's feet. He lifted his heavy, now size 16, hairy feet. They felt heavy and walking with them was taking some getting used to. Then he felt the tingling sensation traveling up his legs as he saw thick brown hairs sprouting around his ankles, slowly crawling up his legs.
The forest of tangled brown body hair was erupting out of his legs, making them look almost animalistic! It rose up and up his legs. Veins shot up and down as his calf and leg muscles became huge, although you couldn't really see them under the hair. Soon the hair was up to his knees and growing even further. He felt a pulling sensation in his legs. Were his legs getting, shorter? He reached down and rubbed the hair on his thighs, as the brown hair grew even higher up. It felt so kinky and thick. "Ugh, what have I done!", he thought to himself as the hair grew higher and higher up his thighs, and he felt a strong tingling sensation in his crotch. Examining his crotch, he sees his balls looked bigger, and was his cock longer too? He looked in amazement as he saw a bunch of thick brown hairs start to squirm their way out all over his ball sac. The heat in his crotch got even more intense. Oh gosh, was he growing caveman balls and a cock? Jeff started to panic as he stared at his crotch in fear to the changes that were about to happen...