Mike was lead to a large enclosed pature where a small herd of heavy horses was grazing. The the approach of the gray Knight, one fo the animal broke from the herd and trotted over. Like Mike, he was a magnificent black warhorse stallion, though his muzzle was gray and his hide bore old scars. Even so, he was a handsome beast, and obviously in good shape. Mike knew little about horses, but he was sure they didn't normally live 50 years.
The Kinght dismounted and opened the gate into the pasture. "You have several choices. If you choose not to enter the pasture at all, you will be gelded and allowed to serve as a farm animal for the rest of your days. You will be well treated, and enjoy a long and reasonably contented life as a plow horse."
"Once you enter the pasture, you will be challenged by the lead stallion. If you lose the fight, or choose not to fight, you will become a mare, and the stallion will mount you and make you pregnant. You will be subservient to the stallion, and again, live a long and healthy life as a brood mare."
"However, if you win, you will become the new herd Stallion. You will have to fulfill your duty of mounting all of the mares until they are pregnant. When that is done, you will have the choice of remaining herd stallion, or returning to your world as either horse or human."
"You must choose now."