Tommy Barrett is a dreamy-eyed fifth-grader who lives with his parents, twin brothers, two cats and a turtle in San Jose, Calif., the heart of Silicon Valley. He's an honor-roll student who likes math and science and video games. He's also a world-class expert on Animorph and Transformer toys. "They're like cars and trains and animals that transform into robots or humans--I love them!" he shouts exuberantly.
And that is sometimes a problem. For a time, in fact, Tommy's fascination with his toys was so strong that when they weren't around he would pretend to be the toys, transforming from a...