Dirty Rat is the one hundred and twenty second episode of the series. It first aired on the 3rd September 1996.
Rat is all dressed up for a fancy dinner at the Teddies' house, which the bananas have also been invited to. The bananas overhear him taking about his elegant clothes but hear him say “Elephant” instead. They then admit that they don’t have any “elephant” clothes to wear to the dinner.
Rat tells the Bananas that they can’t go to an elegant dinner wearing their pyjamas. However, the bananas say they’ll probably have to, as they don’t have any “Elephant” clothes (or any clothes, since they only ever wear their pyjamas).
Rat drops his hat into a tin of chocolate powder. Then, while looking for a flower in the park to put in his jacket, Amy shovels dirt onto him by accident and subsequently touches it with her muddy hands, dirtying his jacket. He then falls down into a dirty puddle, dirtying his trousers and crushing the flower.
The bananas feel sorry for him and take him into his shop to get him cleaned up. They find him a new hat and a fake flower, but Rat says that he has no clean clothes to wear. The bananas assure him that they have plenty of clean, "special" clothes in their house that Rat can borrow.
When Rat arrives at the special dinner, he is wearing a pair of B1’s pyjamas. He feels very embarrassed about wearing pyjamas to an elegant event, but the Teddies and the bananas assure him that he looks very "Elephant". They all enjoy the special dinner.