Horror Show Meaning

(idiomatic, by extension) A horrifying, appalling, or sickening experience, set of events, or visual spectacle.

Example: A horror movie or television show or other performance which depicts gruesome, horrible, or disgusting events, especially in a vividly visual manner.
1991 Jan. 14, Claudia Wallis, "The Rough Road to Recovery," Time (retrieved 18 June 2015):
  Colleen Fallscheer, a cheerful 40-year-old mother of two from Waterford, Mich., is living proof that breast-cancer therapy is not the horror show it used to be.
2011 Sep. 10, Lewis Stuart, "Nervous Scotland secure victory," The Times (UK) (retrieved 18 June 2015):
  A good start, a strong finish, but it was a Scotland horror show in the middle as the team flirted with Rugby World Cup humiliation.
2014 Dec. 26, Fakhrurradzie Gade, "Countries mark 10 years since Indian Ocean tsunami," Boston Globe (retrieved 18 June 2015):
  Survivors waded through a horror show of corpse-filled waters.