goblin vs will o' the wisp

goblin

noun
  • One of various hostile supernatural creatures, now especially (fantasy literature) a malevolent and grotesque diminutive humanoid, often associated with orcs or trolls. 

will o' the wisp

noun
  • A flickering light or lantern, especially over bogs, swamps or marshes, held by a supernatural creature who uses it to lure travelers at night to their demise. 

  • A delusionary or otherwise unachievable goal that one feels compelled to pursue. 

How often have the words goblin and will o' the wisp occurred in a corpus of books? (source: Google Ngram Viewer )