Jack carefully contemplated what to do with the ring next. After some time thinking, he devised the best way to approach his next wish.
"Alright, humans no longer have udders."
The ring did as instructed. The change he had reversed itself almost instantly. He then prepared himself for the massive change he was about to make.
"Until I say otherwise, humanity will devolve by 5 million years."
Before Jack's eyes, instantly civilization vanished. He was now standing in what appeared to be a tropical forest naked. It was then that the physical changes started.
Jack started to shrink until he was only about 4 feet tall. His arms lengthened as his feet became more hand like. It was still possible to walk upright, but not for very long distances. Jack's brain shrank as his skull became more ape like. All of his human memories fizzled away, leaving him a little less intelligent than your average chimp. His penis only shrank a little as his balls grew in size. Finally, brown fur grew all over, covering most of jack's body.
Within the span of a few minutes, humanity had reverted all the way back into apes. The entire ordeal had made Jack extremely horny. He grabbed his penis and started to masturbate. As he was ooking with pleasure, he noticed a female member of the species running on all fours towards him....