As the wheelchair comes tearing down the hill toward the cliff, there is a look of genuine fear in the eyes of its occupant, 12-year-old Jade Category. A stunt double will take the plunge into the water below, but in the next scene it is Calegory, a victim of spina bifida and scoliosis, who is flailing his arms in the water and trying to stay afloat. "I held my breath under water and counted about five seconds and then came up," says the plucky Calegory, star of Mac and Me. "They were gonna have someone pull me down and then push me up, but I said, 'No way, I don't need it.' Still, I was kind of freaked out."

Acting is only the most recent expression of Calegory's fearlessness, and though his new movie is, at best, a grade-B E.T. clone, it's a giant step for the energetic seventh grader from California. "The movie shows that these kids can get in a chair and play," says Jade's mom, Kathryn, a real estate broker. "They don't have to sit in front of a TV. Jade just plays the part of a regular kid, and it took a lot of courage to do that."

In his 12 years, Jade (a nickname drawn from his initials, J.D., for James Dominic) has had to muster more than his share of inner strength. He has suffered through 16 operations, including a lifesaving spinal fusion, and has spent most of his life in body casts or a wheelchair. But he has been unrestrained in his determination to lead a full life. When he was 5 and covered from chest to knees in a cast, he was fond of skateboarding down hills on his stomach. After hearing about the achievements of Jim Knaub, a world-class wheelchair racer, Jade was inspired to get his first wheelchair. Before long he had mastered wheelies, and at 7 he entered his first of nine 10-kilometer races, two of which he has won.

In addition to his role in Mac and Me, Calegory is serving as spokesperson for the Easter Seals Friends Who Care program, which is intended to educate children about kids with disabilities. Despite his success, there is little danger of Jade going Hollywood. Though he says he likes acting because he can "be something different," he doesn't confuse himself with his movie persona. And he would prefer to be something alive. "I would never," he says reassuringly, "go flying off a cliff."