Super Mario Sunshine/Delfino Airstrip

Watch a scene, and after that go to the corner of the airstrip without touching the goop and get FLUDD and watch yet another scene. Once the scene is over, go over to the goop and spray the center for a short time until a Goo Monster comes out. To defeat it spray its mouth three times and out comes a Shine Sprite. SHINE! Save the Pianta in the goop if you want. Now watch another scene. You will now be in Delfino Plaza.