* AluminumChristmasTrees: The plot point about Red Razberry Zingers dying children's digestive tracts red is based on a real incident: when [[Advertising/MonsterCereals Franken Berry Cereal]] was first introduced in the early 1970s, it included an indigestible pink dye that turned many children's feces pink, prompting General Mills to change the recipe.
* GeniusBonus: [[spoiler:After Cujo's death, Brett gets a new dog named "Willie". Cujo himself is named after the American domestic terrorist Willie Wolfe, who was known to the press by the alias "Cujo" (a misspelling of his actual alias "Kahjoh").]]
* ItWasHisSled: [[spoiler:Tad dies, subverting ImprobableInfantSurvival]]. A hugely unexpected gut-punch at the time, but now one of the most well-known things about the book. Stephen King has discussed the ending in a few of his ''Entertainment Weekly'' columns, and even spoiled it in one of the ''[[Literature/TheDarkTower Dark Tower]]'' books (where [[AuthorAvatar he appears as a character]]).
* MemeticMutation: "Cujo" became a catch-all term for rabid or otherwise dangerous dogs in the eighties.
** The book itself has become a real example of "writers on drugs" jokes, due to King being [[ThisIsYourPremiseOnDrugs high on cocaine]] while writing.
* ParanoiaFuel: And how. Better make sure your dog's vaccinated...
* RealismInducedHorror: If you're a dog owner, or know a dog owner, the premise of a rabid St. Bernard violently attacking its owners, comes off as extremely unsettling.
* ThisIsYourPremiseOnDrugs: King actually ''was'' on drugs while writing the novel (to the point that he has no memory of writing it), but despite this, it isn't surreal or incomprehensible.[[note]] Understandable, considering his drug of choice at the time was ''cocaine'', which doesn't generally result in an altered or impaired perception of reality.[[/note]] This also put him in the unusual position of being able to read one of his own books just like an unspoiled fan, and he ended up saying he really likes it and wishes he could remember the writing process.
* TrappedByMountainLions: Ironically given the trope name, Donna and Tad trapped in their car ''is'' the main plot that the reader is supposed to care about, yet the book keeps cutting away to Vic's attempts to save his ad agency and Charity's visit to her sister, both of which are of almost no consequence to Cujo's rampage and only exist to get certain characters out of the way before it starts. This is perhaps the one clear sign that King wasn't quite in his right mind while writing it.
* TheWoobie: Poor, poor Cujo. He really was a good dog that loved people very much who just ended up in the wrong place at the wrong time. Seeing the world in his perspective as he starts descending into rabid madness is even more tragic because he was never a bad dog at all, and he sadly thinks he is a bad dog after he gets bitten (believing that it was his fault, and that he will get in trouble for breaking some kind of rule). From reading Cujo's perspective, he comes off as a young child who simply can't speak.
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