The ring comes off and I make a wish!
I then wished that Cassy would shrink to my height and I would grow to hers and then I also wished that the ring would never come off me ever again and that it would stay with me always by either staying on my finger or disappearing and it still being there in my mind so I would never lose it.
When I made the wish I felt myself growing and I saw Cassy Shrinking.
"Noooooo you evil little bitch!" she cried as she shrank.
When the transformation was complete I was a fully grown adult woman with fully developed breasts while Cassy was a tiny girl no bigger than one of my fingers.
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What happens next?