"Boo's Big Growl," little monster Boo, with the support of her big sister, Creepy, finds the self-confidence she needs to show the world her GROWL! The Monstrous Adventures of Creepy and Boo, are a charming line of books, meant to inspire, empower, and educate young readers 5-10 years old. The stories are based around the two Monster sisters, Creepy and Boo, who support each other through the day to day trials of today's youngster.