Wubbzy is too small to play hoopty hoops, ride the loopy rollercoaster and see over the people in front of him at a movie. Widget builds him the Big-O-Matic 3000 which makes Wubbzy bigger. But soon he would change his mind about it after he gets too big. Near the end, he is growing but not stopping and almost gets too big to fit in the bigger Big-O-Matic that Widget makes. He manages to squeeze in so they shrink him back to normal size which is, as Wubbzy says, "Wubbzy-sized".
This was the last Season 1 episode in production order.