No Rest for a Pest - S1.E10

Peter and So-So land in a medieval-age town to get food. They can't get food without money so they get a job removing a pest for the king. The pest is a very difficult to eradicate dragon. They disguise themselves as a lady dragon to lure out the dragon. That strategy works too well and they run back to their balloon and take off. They are chased by the dragon in mid-air because it still sees the lady dragon costume.