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The novel stated that most animals revived just come back 'off' rather than explicitly bad, Jud explicitly states that everything he's heard of that was brought back to life came back mean and cruel, and also acknowledges that the place has the power to twist minds so that they tell themselves it might work out better this time. This is explicitly demonstrated in Church, who far from the stinking, slightly dull cat of the novel or the hissing glow-eyed feline of Pet Sematary (1989), is actively malicious. It's implied that Church lured Ellie out into the path of the truck in revenge for Louis abandoning him outside of town.
During Ellie's birthday party, Jud can be heard in the background saying, "There was a big Saint Bernard... killed four people". This is an obvious reference to Cujo (1983), another movie based on a Stephen King novel.
When Rachel is returning home from Boston, there is a highway sign that says "Derry 20 miles". Derry is a town that appears in numerous Stephen King stories, most prominently in "IT."
Animal trainer Melissa Millett revealed that a total of five cats, all rescues, were cast to play Church, although ultimately one of them dropped out after getting scared on the set. The feline actors were accommodated in five trailers, along with their human trainers, although one had to be kept in a separate trailer from the others because it did not get along with its cast mates. Millett noted, "The only good working cat is a happy cat...They were quite spoiled." The film crew even built an area near the trailers, nicknamed a "catio," where the hard-working kitties could play and relax between takes. The cats spent two months in training for the shoot, which took around 10 weeks. Aside from the one cranky cat, the rest reportedly got along well with each other and with the movie's human stars, including Jason Clarke and John Lithgow. The quintet of feline stars all found homes after the shoot was done: two were adopted by the movie's animal coordinator, Millett found homes for another two with friends, and kept one herself.
Referring to the original adaptation Pet Sematary (1989), Stephen King has stated that of all his novels, this is the only one that genuinely scared him.
According to an article in The Hollywood Reporter in October 2019, Paramount reportedly decided to push forward with a remake when they received a termination notice from Stephen King for their rights to the book.