banana skin vs danger

banana skin

noun
  • A cause of difficulty, or potential embarrassment. 

  • The outer skin of a banana, especially once removed from the rest of the banana, which may be slippery if stepped on. 

danger

noun
  • An instance or cause of likely harm. 

  • The stop indication of a signal (usually in the phrase "at danger"). 

  • Exposure to likely harm; peril. 

How often have the words banana skin and danger occurred in a corpus of books? (source: Google Ngram Viewer )