George Brown and the Protector — Duane L. Ostler

George Brown is an ordinary boy, attending an ordinary school, climbing ordinary trees, and eating ordinary pizza-until he meets a bizarre alien known as "The Protector." Suddenly life for George is anything but ordinary. Now George and the Protector must unravel the secret of a fallen star, find George's missing father, and unlock the mysteries of a small stone which contains fantastic powers.