Big...Little...

Zibbi and I were reading a book about big and little.  (By the way, Zibbi LOVES reading books.  We seem to have a houseful of book lovers!)  I read the first couple of pages which went something like...Big Bear.  Little Bear.  Big Dog.  Little Dog.  We arrived at the third page, I said, "Big Cat..."  allowing Zibbi to join in on the fun.  To my surprise, instead of saying, "Little Cat", she exclaimed, "poop".