* The entire sequence of Xuan Wu taking female form. In particular Bai Hu's reaction to the news.
* Pretty much the pranking that goes on between Emma and Leo throughout the series. This even occurs well into the seventh book.
* After Black Jade takes on his/her proper stone form (along with name and human form) in Dark Serpent, they suggest shortening its name to BJ. Everyone else laughs at the InnocentInnuendo, while it takes Amy a while to catch on.