You are on a hunt to find Pheromosa, one of the ultra beasts. You decide to search Verdan Cavern, because thats where you've heard most rumors about Pheromosa lurking. And, to your surprise, you somehow find a hidden room with a little lake(?), and Pheromosa is just sitting there, her arms up against the back of the wall behind her as she rests in the small body of water.