Paul struggled back from the water and the reflection that showed him turning into an animal. As he tried to process this impossible change, he saw a dark form lumbering his way. A bear! Then the heavy odor of the approaching beast filled Paul's nostrils and he was suddenly attracted. The former teen stood still as the huge male approached - this was a mature animal, many seasons old, a veteran of the woods. There were fewer seasons left than it had already lived, but it was still a virile and effective mate.
Puck grinned as he increased the speed of Paul's transformation, and made some adjustments as well. The former boy began to get larger, maturing as he changed sex and species. The male snuffled at Paul and approached, aroused by the scent of a female in need. At the same time, Paul found himself both curious and somehow knowing what to expect - as if he had been mounted many times before. He remembered many pregnancies, the feel of cubs nursing from his teats, the sense of giving birth. In his confusion, the changing teen realized he was becoming a mature bear, not the young equivalent. In a few years, the female bear he was would be old. And when he died, it would be as a bear, so whatever afterlife he found would be that of a beast.
Yet he started to respond to the male, wanting the seed that would create more cubs within him - her. Puck flitted off the she-bear's head as the two animal snuffled each other. The Fae grinned as he sensed resignation from the transformed human, and then acceptance as the big male mounted her. They would mate several more times tonight, and then the new she-bear would wander into the forest to carry and eventually deliver and raise her cubs. By the time the male roared as he delivered his first jest of semen, the she-bear that had been Paul was fully the beast, content and unaware she had ever been anything else. And the existence of Paul vanished from the world, replaced by that of a bear.