These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Nightmare Fuel: "Lab Animal" in both. "Primal Self" in the book. To clarify on the former, it features a Painful Transformation sequence wherein the cat transforms into a dog (with an unnerving Uncanny Valley effect at the end of the book version when said dog stares at the reader, revealing its cat's eyes). In the latter, "Tigger" is corrupted by these savage feline monstrosities. The story ends with the implication that "Tigger" is going to violently murder his elderly owner, the last shot showing "Tigger" leaping at her from behind.