Arnold and Becky

Arnold lives at 305 Woodridge Road in the town of Glen Brook, Illinois. His caretakers are Libby Thatcher, an ad agency account executive; Drew Thatcher, the owner of the Glen Brook Grill (lots of doggy bag goodies every night for Arnold) and the family's children Paige, the eldest daughter, Becky (14), and Charles "Corky" (18) who has Down syndrome.

Arnold likes to carry his red bowl around the house to remind his owners to give his some dog food. His mission in life is to be fed. 

Bullet the dog played the role of Arnold the "Semi-wonder dog". Bullet was originally owned by animal trainer Richard Calkins who got Bullet from a friend when the dog was three months old.

Bullet was later adopted by Joann Curtis, the daughter of the late Lassie trainer, Rudd Weatherwax who retired Bullet from show business as a family pet. Bullet lived with Curtis for fifteen years until his death of kidney failure in 1999.

On the set, Bullet was a very affectionate and got along extremely well all the cast members, especially Chris Burke who was very fond of Bullet.

Off the set, Bullet loved to watch cartoons (Tweety Bird was a favorite) and enjoyed eating pizza crust from Palermo's in Hollywood.

Bullet's other acting credit included a commercial for the Arizona state lottery.