Definition of "phantasmagoria"

phantasmagoria

/ˌfæntæzməˈɡɒɹi.ə/

noun
plural phantasmagorias
1. (historical) A popular 18th- and 19th-century form of theatre entertainment whereby ghostly apparitions are formed.
2. A series of events involving rapid changes in light intensity and colour.
3. A dreamlike state where real and imagined elements are blurred together.
  Quotations
  this mental phantasmagoria
  1815 February 24, [Walter Scott], Guy Mannering; or, The Astrologer. […], volumes (please specify |volume=I to III), Edinburgh: […] James Ballantyne and Co. for Longman, Hurst, Rees, Orme, and Brown, […]; and Archibald Constable and Co., […]
  It is impossible to convey, in words, any idea of the hideous phantasmagoria of shifting limbs and faces which moved through the evil-smelling twilight of this terrible prison-house. Callot might have drawn it, Dante might have suggested it, but a minute attempt to describe its horrors would but disgust. There are depths in humanity which one cannot explore, as there are mephitic caverns into which one dare not penetrate.
  1874, Marcus Clarke, For the Term of His Natural Life Chapter V