"Yes, I am the wizard you are seeking. But before I can help your party, I must break the curse that has trapped me here as a stable boy." Llandros gestured at the little boy. "We need someone wiling to become a warhorse for Aaron. Up to now, no one has been willing to become an animal. Anyone from our world would be stuck as a beast forever, and the very act of transformation would make them fully a horse in mind as well as body."
That did not sound like anything Mike wanted, either. "Uh, look, I'd like to help, but I don't want to be stuck as a horse, especially if I don't even remember being human."
Llandros nodded. "And I would not ask you to, no matter how desperate my young warrior friend here is." Aaron looked crestfallen. "However, the rules of magic do not apply to you the same way because you are not of this world. Being transformed into a beast would still cause some mental changes, but you would retain your identity and memories. And while such a transformation would be irreversible for someone of this world, the magic that locks in the form would not follow you back to your world when you return."
Mike tried to work this all out. "So, I can become a horse and remember my past and being human, and I can be changed back to my normal self when I return to my own world?"
"Yes, for the most part." The boy wizard sighed. "Your Wizard Tye gave you that form because you like transformation, and horses, correct?"
Mike nodded, then flushed slightly. "I guess I tend to end up on hooves in most of our games. Often horses, but sometimes minotaur and satyrs, or goats and bulls. Once a cow."
"Then there is a reasonable probability that you would like being Aaron's warhorse very much." Llandros smiled slightly. "A magnificent stallion, a black Shire, possibly the finest warhorse in this world. You would have knowledge of years of training, provided magically, and while you would remember being human, an equine past would also exist to provide you with a proper reference in this world."
"That sounds pretty good." Mike agreed. "I'd love that!"
"Then change him! Make him my horse and break the spell!" Aaron shouted impatiently, stamping his foot like a petulant child.
"I have to be honest with you, as I am a Green Wizard." Llandros smiled slightly. "The warhorse identity and form will be easy to accept, and the more you settle into it, will be more and more natural to you. Given your prior interest, you are very likely to prefer being the Shire, and allow your humanity to fade voluntarily. You could end up a very smart war horse by choice."
Mike thought about it some more. "So, the danger is that I will like being a horse too much? Does that mean I would not be able to change back once I got home?"
Llandros shook his head. "It is deeper than that. You might not want to be changed back."
Mike looked at the anxious little red-haired boy and the boy wizard. If he went along with this, his adventure would gain a wizard and a warrior, and he would get to experience being a magnificent warhorse. He wasn't sure he believed that life as a stallion would be so great that he would never want to change back, though. Even it is was true, was that such a bad thing? To love being a horse too much? It sounded like he would be truly happy.
After thinking silently for a few minutes, Mike finally nodded to himself. "OK. There are risks no matter what I choose. So I have decided that..."