Rabbit kids

The rabbit kids are the children of an unnamed mother. There are a total of eight of them. They come with their mother to Elwood City from Shelbytown when she delivers to Arthur her copy of the novel when she saw his request for it on an online message board. Right before she leaves, the children all wave at Arthur from the car. When Arthur starts reading the novel, he discovers that the kids have scribbled in it to the point of making it unreadable, much to his dismay.

Trivia

 * The mother having eight kids could be a reference to the fact that real life rabbits are rapid breeders.