A strange liquid that gushes forth air.
To obtain the item, the player must first buy the Bottled Faerie for 50,000 gil at the Caravan, which is located in a desert west of Onrac. They must then return to Gaia and go through its maze-like wooded back area, where the player should eventually find a pond. If one stands by the pond and uses the bottle, a faerie will appear and give the player Oxyale to put in the bottle. Should they return to Onrac and speak to the woman in the southeast corner of the town, near the sea, she will reveal herself as a mermaid's spirit, then vanish and allow the player access to a crude barrel that serves as the submarine transport to the Sunken Shrine.
In the Dawn of Souls version of Final Fantasy, the Bottled Faerie costs 40,000 gil to buy from the Caravan. When you reach Gaia, the faerie leaves the bottle and runs to the pond. When the player catches up to the faerie, she apologizes for running and gives the player the Oxyale in exchange for freeing her.