Received an animated adaptation in the early 2000s.
A widower with a teenage daughter and a widow with a teenage son are getting married. Much to the distaste of their children, who hate each other and find constant reasons to argue. The fixation that Rory, the boy, has on an "appleman" — a doll with a head made from a dried out apple — that is the only thing he has left of his Disappeared Dad is an excellent excuse for Dawn (the girl). And then worms emerge from the apple... worms with tongues. That suck the guts out of other living creatures. And then things get really eerie...
- Artifact of Doom: Rory's appleman, which is infected with the Virus.
- Attack Of The50ft Whatever: Frogs infected by the Virus eventually sacrifice themselves to one of their own, to turn him into a monster-frog large enough to swallow humans whole.
- Body Horror:
- The effects the Virus has on human beings. They grow increasingly covered in thick white mold, which starts eating away at their flesh. In the animated series, it actually promotes the appleman from "Artifact of Doom" to "Big Bad" by changing Rory's dad so he's driven insane and develops a head exactly like a half-eaten apple.
- The description of victims of Slobberers. Having your entrails and flesh sucked out of your body through holes bitten in your skin is not a comforting thought.
- Cool Old Guy: Dawn's grandfather, Gramps; a little dotty, but he's the only adult help that Rory and Dawn have in facing off against the Virus.
- Covers Always Lie: The cover for Part 1 has a colossal demonic-looking face looking down on a cluster of skyscrapers and laughing. No part of the actual story alludes to any of this.
- Subsequent covers also had a habit of depicting events that happened in the previous book. i.e. Book 3 has one of the killer sheep on the cover when they were only a threat in Book 2 and Book 4 had the giant frog on the front cover- when it had died in Book 3. By Book 5 this habit has been kicked.
- Disappeared Dad: Rory's dad. It turns out he didn't abandon his family, but left when he realised he was being consumed by the Virus, as he didn't want to infect them.
- Everything Trying to Kill You: Any animal infected by the Virus becomes a homicidal monster. Worms turn into Slobberers, multi-tongued pack hunting predators that suck the internal organs of their victims out through holes they bite in the skin. Sheep have their wool turn into steel wool and become smart enough to use tractors. Frogs willingly feed themselves to the biggest frog so that he can grow into a man-eating giant... A dried-up appleman becomes the source of a monstrous vine-like weed. You get the point!
- Hate Plague: What the Virus is, in a rather zigzagging way; it drives those who are infected with it to feel hatred, and grows stronger by feeding off of their hate and rage, which allows it to mutate its victims as they become more and more hate-filled.
- Mental Time Travel: When Rory gets infected by the virus, he always time-travel back to the day of the bus-accident.