Z is For Zero: The Story of the Petrified Bear

Z is For Zero: The Story of the Petrified Bear is a book by Rick Riordan about Ursus, son of Artio, the Celtic goddess of bears. He is turned to stone in attack pose while standing because of a Cockatrice that invaded the Black Forest. Kinsey Millhone, the detective of Santa Teresa, must team up with Percy Jackson, Carter Kane, and Magnus Chase in order to protect the bear who was turned to a stone statue forever from the forces of Luke Castellan.