nightmarish vs phantasmagoric

nightmarish

adj
  • Resembling a nightmare. 

phantasmagoric

adj
  • Characterized by or pertaining to a dreamlike blurring of real and imaginary elements. 

  • Characterized by or pertaining to rapid changes in light intensity and colour. 

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