Andy and Terry have a new book to write, but there's a problem. A BIG problem. Well, quite a few big problems actually.... On a hill not too far away there is a tree. And in that tree there is a tree house. And in that tree house there is a bowling alley, a see-through swimming pool, a tank full of sharks, a giant rope swing, a library full of comics, a secret underground laboratory, a vegetable vaporiser and a free marshmallow-dispensing machine.

Ever tried to get out of going to school by pretending that you're dead? Ever managed to convince a friend that they're invisible? Ever been stuck in a gorilla suit and nearly put in a zoo? Andy has. Andy's the greatest practical joker in the world ... well, almost. He would be, if only his practical jokes didn't have the annoying habit of backfiring on him.

From the world’s favourite author, David Walliams–ten cautionary tales and a delightfully dreadful cast of characters. Are you ready to meet the World’s Worst Children? Five beastly boys and five gruesome girls!

 Fourth graders George Beard and Harold Hutchins are a couple of class clowns. The only thing they enjoy more than playing practical jokes is creating their own comic books. And together they’ve created the greatest superhero in the history of their elementary school: Captain Underpants! His true identity is SO secret, even HE doesn’t know who he is!  

The beloved World’s Worst series has captivated millions of readers. You’ve met the world’s worst children, the world’s worst parents, the world’s worst teachers and the world’s worst pets – but are you ready for the world’s worst monsters? If you don’t like ghosts, ogres, zombies, vampires, aliens, werewolves or mummies, DO NOT LISTEN TO THIS BOOK. Laugh along to these ten terrifying tales of marvellous monsters, brought to you by David Walliams.