Seems that Rose has picked up a strange glowing jewel and worn it as her new earring. Transforming her body into that of a big, buff two tailed demon cat. Seems the transformation has given her quite the boost in size, strength and bust size.
I'm not sure if she can get much bigger without outgrowing the room she's in.
Moral of this story: Never mix items from different animes together. I swear it's like crossing the streams in Ghostbusters. >,..,<