monster vs nightmare

monster

verb
  • To behave as a monster to; to terrorise. 

  • To harass. 

  • To make into a monster; to categorise as a monster; to demonise. 

  • To play (a series of) non-player characters as directed, without having the responsibility of organising the game itself; generally not limited to playing literal monsters or hostile combatants. 

noun
  • A terrifying and dangerous creature. 

  • A bizarre or whimsical creature. 

  • A cruel, heartless, or antisocial person, especially a criminal. 

  • Something unusually large. 

  • A prodigy; someone very talented in a specific domain. 

  • A badly behaved child, a brat. 

  • A non-player character that player(s) fight against in role-playing games. 

adj
  • Great; very good; excellent. 

  • Very large; worthy of a monster. 

nightmare

verb
  • To have a nightmare. 

noun
  • Any bad, miserable, difficult or terrifying situation or experience that arouses anxiety, terror, agony or great displeasure. 

  • A very bad or frightening dream. 

  • A feeling of extreme anxiety or suffocation experienced during sleep; Sleep paralysis. 

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