Nightmare Fuel: Practically the whole book. Koontz is usually big on environmental and atmospheric description, and he uses it to uncomfortable advantage here. Some of the scariest bits involve Jenny and Lisa's initial exploration of the empty town, even before they find more bodies. The Take Our Word for It deaths of many of the soldiers also serve to make them more horrifying than it would have been if he'd shown it.
Trapped by Mountain Lions: Any chapter containing the character Fletcher Kale. It's made even worse by the fact that, with the exception of the first chapter Fletcher appears in and the final epilogue chapter (where they attempt to assassinate the protagonists), he and his fellow psycho Eugene Terr never interact directly with any of the other main characters at all, and nothing else in the story would have been affected if they had been cut. It's hard to find the escape of a murderous sociopath the least bit compelling, or find the character the least bit menacing, given the Eldritch Abomination everyone else is dealing with several dozen miles away.
Harsher in Hindsight: The constant sexual harassment that Lisa gets from Stu became this when Rose McGowan revealed that Harvey Weinstein raped her during production.
Memetic Mutation: Good luck ever mentioning this film online without being told that Ben Affleck was "the bomb" in it.
Narm: Replica!Stu's scene in the movie is pretty funny, starting with him singing "I Fall To Pieces", interrupting it with a pretty Large Ham "OUCH!" and especially when he yells out "IT'S LIMBO TIME! HOW LOW CAN YOU GO?!" while chasing the heroines with Combat Tentacles.
