bug-a-boo vs goblin

bug-a-boo

noun
  • A mythical, nocturnal creature; a hobgoblin. 

  • Any imagined fear or threat, or a fear presumed larger than it really is. 

goblin

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

How often have the words bug-a-boo and goblin occurred in a corpus of books? (source: Google Ngram Viewer )