Beware, all grown-ups who are contemplating being mean to a child. Do so at your peril. Pay no heed to this warning and you’ll be in for . . . the Giggler Treatment! In this funny, very silly, and very gross story for middle graders, Booker-winning Irish author Doyle (for adults, A Star Called Henry, 1999, etc.) proposes that dog poo—a word he deeply enjoys using and describing—lays around for the punishment of adults who are unkind to kids. The Gigglers, color-changing, elf-like creatures, have, since the beginning of time, paid dogs (or other animals) for their droppings and left the stuff around so that unsuspecting, mean adults might step in it. Mr. Mack, the intended victim here, is about to be “treated” on his way to the train station because he sent his two sons to bed without dinner the night before. In painstaking detail, readers are given a running countdown of how many minutes and inches are left before Mr. Mack’s foot hits its mark. At the last moment, though, when the boys explain away their father’s behavior, the whole Mack clan, the Gigglers, and Rover, the dog who anted up, give wild chase to the station, via Egypt and Paris, to prevent the disaster from happening. Piled with words that denote a variety of body functions and wastes, this ludicrous book should more than please the most fervent among the gross-out set. Wait till they see what passes for chapters here, too: one’s named for the author’s mother (so that he could stay up late) and another, for his refrigerator. Includes an exquisitely wacky glossary. (Fiction. 7-11)