This is a less offensive way of saying "Jesus Christ"
It originated with the movie 'The Faculty'. In the real version, one of the characters exclaimed "Jesus Christ!" but in the edited TV version, they had it changed to "Cheese and rice!"
OKKK FINEEE ILL EXPLAIN.
So basically moony transforms into her other form and ena is surprised so she says- "CHEESE N RICE MOONY"
Search it up on youtube.