hobgoblin vs ugly duckling

hobgoblin

noun
  • A small, ugly goblin that makes trouble for humans. 

  • A source of dread, fear or apprehension; a bugbear. 

ugly duckling

noun
  • A young person who is ugly, but who is expected to become beautiful as they mature. 

How often have the words hobgoblin and ugly duckling occurred in a corpus of books? (source: Google Ngram Viewer )