Stacy Hirano's cousins are seen when Phineas Flynn and Ferb Fletcher stopped by Tokyo during their travel around the world. When they visited Stacy's relatives it is revealed that Stacy has many cousins. The relatives then start to sing "J-Pop (Welcome to Tokyo)", during which Phineas asks for some vegetable oil to refuel their plane and take off. ("Phineas and Ferb: Summer Belongs to You!" S02E0101)