Arthur's Lost Dog is the second part of episode 12 of season 1. It day viewed with Arthur Writes a Story on November 25, 1996.
Summary[]
It is Downtown Day in Elwood City and the Reads are downtown attending the event. They pass a clown carrying balloons and Kate begins crying because she wants a balloon from the clown. Nobody in the family but Pal knows that. Pal runs off after a clown to get a balloon, but Arthur thinks he is running away from him.