- Anvilicious: Particularly when it comes to Christian themes or Libertarian philosophy.
- One Door Away from Heaven suggest anyone who in any way, shape, or form supports utilitarian bioethics is the next thing to a Nazi.
- Fridge Horror: In Dean Koontz's novel Relentless, as a child the main character witnesses the brutal and senseless murders of almost his entire extended family at the hands of his estranged uncle. Not only that, he makes the bodies presentable before going upstairs and taking a nap before calling the police. Even he himself wonders how he managed to live a normal life after that.
- Hilarious in Hindsight: Darkfall, which was released in 1984, features a protagonist named Jack Dawson.
- Moral Event Horizon: Koontz is willing to do whatever it takes to ensure that the readers absolutely despise the villain and everything the villain stands for. Sometimes he goes too far, and takes his villains into Bad is Good and Good is Bad territory.
- Nightmare Fuel: The Retro Virus in Fear Nothing and Seize the Night, and what it does to the infected. Also the things that occur in the egg room in Fort Wyvern. Plenty of his villains and their actions are worthy of mention. Chances are if its a non-satirical Koontz story, parts of it venture into very scary territory.
- Paranoia Fuel: The entire plot of False Memory, especially for anyone who has ever visited a therapist. The Big Bad is a psychiatrist who mind rapes his patients and forces them to do all kinds of things for his own entertainment. He implanted many of their phobias in the first place, and once he's done screwing with them (sometimes literally), he often drives them to creative suicides and/or homicides. He was doing this for twenty years before somebody finally figured it out.
- Shocking Swerve: Unfortunately this is how many, many of the conflicts in his stories are resolved. When his heroes are facing impossible odds, he'll have an angel show up, or reveal that an autistic child has superpowers and teleported the villain away or can summon and control bats.
- The original Frankenstein trilogy ended with one of these. Suddenly there was a super-powerful "reject" creation that grabbed Victor and solved everything!
- Tear Jerker: Numerous moments can qualify, especially those involving apparent character deaths, flashbacks, or musings on the world at large.
YMMV / Dean Koontz