The prince shoved past the evil queen to his transforming sister. "Fight it Galla! You are strong, I know you can defeat this evil!" he urged. Not being able to see her eyes, the prince bent over and ran his hands upon his sisters black hair, moving it behind her now equine ears. He held her still mostly human face in his hands, tilting her head up so she looked at him. Her eyes were closed, but upon his touch Galla opened her eyes.
"I...I can't beat this Palador! It's too strong. The...arrrg!" Princess Galla dropped her head, her expression on of fierce determination. Her leg twitched and stomped upon the ground. The prince watched in horrid facination as his sister's feet slowly changed into hooves.
"No!" the prince cried "Are you in pain?"
The princess looked up at him with despair. "No, it's horrible. It feels GOOD. I'm trying to fight it, but my body is betraying me" she sobbed. "Oh god! Mmmmmmm...no!"
The prince stood up tall. Glaring at the evil Queen Beth he then turned his gaze down to his sister, on all fours. Another loud stomp upon the hard floor cause the prince to look at Galla's feet once again. They were no longer remotely human. Galla sobbed, then moaned. Palador stroed her head and growing neck to sooth her. "It's OK Galla. It will be OK. Don't give up. Just don't give up."
"You...you don't understand." Galla cried, moaning once again. Her tail swished to one side.
"It is hopeless young princess," the evil queen cackled, "you feel the animal spirit. It's instinct flows within you. You may be strong, but it is stronger. It has always been a part of you, you know that now." Turning to Palador she mocked, "So virile prince, you won't save her from this fate?"
"You will never win evil queen!" Palador cried. "Nor shall you make me commit that dastardly deed. My sister shall triump over you!"
"Oh, I think not foolish boy." Queen Beth laughed as she saw the princess lower her head on the the prince's hard cock bobbing before her.
"Oh! Mphfff....mmmmmm." The prince was taken completely by surprise. "No Galla, no. Oh God." but Princess Galla took his throbbing cock in even deeper, lost within the animal spirit's calling for pleasure, for sex. Her legs and arms began to change into that of a mare's. Palador knew he had to resist, to pull his cock from Galla's eager mouth, but he couldn't make his body respond. He knew he was leaking precum in his sister's mouth
"Oh...so good, so good." the princess mumbled as she stopped for air. "I...I feel the spirit hesitating. Your cum Palador, I need your cum! That's what the sorcerer must have meant. But I have to resist. I must beat this on my own. We can't...we can't. But I feel so horny. God no!"
The princess spun around on her four horse legs. The transformation was slowing, but was continuing. Her size and her face were all that really distinquished her from some common mare. As Palador stumbled backward, his mind in turmoil and body confused, Galla raised her tail, exposing her eager pussy. She didn't know if she was doing this of her own accord to fight the spirit, or if it was the spirit itself driving her to procreate.
"Please Palador, I need you" she pleaded, looking over her back to the naked prince. Her eyes were filled with tears. "I....arrrg!!!" Her face began to change, nose transforming into nostrals, face extending.
The prince stood there for a moment. His cock driving him to penetrate the eager pussy before him. His mind confused whether to give her his seed in hopes that the queen was truthful that it would stop his sister from becoming a mare, or resist the queen's desire for him to commit the unspeakable act of incest.