...a donkey.
For a while, nothing really happens. That didn't stop Circe from smiling deviously at Prince Damon. The prince, however, was confused and rather insulted to be called her pet.
"Well, I've had enough childish antics from the likes of you, Circe, so I bid you a fairwaaaaawwww-heeeee-haaaawww"
Prince Damon covered his mouth in embarrassment and fear, but that didn't last long as his muzzle was starting to force itself out. His nostrils flared as he took in new smells and his golden beard started to into the muzzle, letting his hair cover his face. His teeth became blocky and thick, making it hard to speak in his current condition.
"Whaaawww-hheeeee is happeneeeee-hawwww?! Make it staaaawwwwp"
Circe was overjoyed as she had a new pet on the island. A donkey suited this stubborn prince. Hadn't he heard the fables? The myths? The news about people reported missing? Of course not. He was an adventurer, like they all were. All adventure, no brains. Circe made sure that he was now embarrassed by his new form. She scratched his chin in a place where all these adventurers gave up and conformed to the changes.
"You are a good donkey. You don't need to be a prince. And Damon isn't a good name for a donkey. I think that I should rename you"
Prince Damon, while stubborn, wasn't going to be a donkey. He didn't give up. He didn't enjoy the scratches at all. Something that Circe wasn't expecting.
"Donkey, you should be my pet. Why resist?"
Prince Damon tried to speak, but it certainly was difficult. "I naaaawwww-heee-haaaawwwwt gawwwwing to beeee-haaaawww yawwwww pet!"
Prince Damon, despite his best efforts, kept changing. His head was entirely donkeified. His flowing hair was now a dirty mane. His skin was covered in grey dusty fur, and his fingers were starting to fuse. Circe was annoyed. None of her techniques were working. He wasn't changing mentally, for some unknown reason. The girls behind Circe were watching in awe, surprised to see someone still retain their humanity even when cursed.
"Donkey. You. Are. My. Pet!"
"Naaaawwwww-heeeeee-hawwwww!"
"YES, YOU ARE!"
"Naaaawwwwww!"
Soon, Prince Damon's body was completely gone. His hands and feet were now hooves, standing on the shredded remains of his royal clothing. The girls walked by him and picked up his clothes and royal jewelry. They were honestly surprised and quite intrigued if he were to remain here to see what would happen to him. Prince Damon's tail swung slowly as an annoyed expression was on his face. He snorted, letting some donkey snot to come out of his muzzle and drop to the floor. He didn't bother to turn around and observe his new body. He was just annoyed, glaring at the woman who did this to him.
"What? You want to be human again?"
He didn't even nod.
"Well, tough luck, my pet"
He went full force towards Circe, acting like the stubborn prince he was. Circe yawned as she disappeared from the prince's very eyes and appeared next to him as she watched him hit his head on a stone pillar.
"You foolish, foolish man. You'll never be human again"
The prince shook off his pain and grunted at Circe, glaring into her gaze.
"But... I will say... you are very different to the other morons who come to this island. I'll give you this... for now"
She snapped her fingers.
Prince Damon's angry brays started to change back into human speech. "I'm naaaaaawwwwt a daaawwwkney. I'll never beeee-haaaww your pet. I'll... I... I'll thank you for returning my voice, but that still does not mean that I'll be your loyal pet, Miss Circe"
Circe was surprised that she was even thanked by the stubborn prince. Maybe he wasn't as stubborn as he looked, both back then and now.
"Tell you what, I'll give you a few challenges and I'll return... most of your human body"
"Most?" he said, as his head cocked to the side and his ears moved to the sides.
"Well, I did say that people never leave this island. And with you being... well, a stubborn male, I'll make you walk on two legs, but you'll still be a donkey"
Prince Damon thought about his current situation in detail. What would happen if he was to say no? Would he still have his voice? What about his mind? What if he said yes but it was a trick that would result in the end of his humanity or the humanity of others. He had to take a risk.
"I accept the challenges. However, you'll have to return the minds and voices of those that have been here before me"
"A toughie but I also accept. I can promise you that. Your first challenge is..."