When you arrive in the shop-filled area that is the southern bank of the Moonflow, open the nearby chest for two Phoenix Downs , then speak with Auron and go west a while. Speak with the Chocobo Knights if you want, then head into the nearby enclosure where Lulu is. Speak with her, then open the nearby chest for 5,000 Gil . Save the game and speak with Wakka.
As you progress back to the boarding area, consider plundering some of the shops for items: very imminently, we’ll be fighting a boss with JUST Tidus and Wakka. It is not ideal to have anything but Lightningstrike and/or Strength +X% on your weapons since the boss resists all but Lightning, elementally. Status-wise, it will be vulnerable to Provoke, but that’s about it. Anyhow, board ze Shoopuf and… Well, what did I tell you?
BOSS - Extractor
The Extractor can be pretty annoying (and a bit of a wake-up call) to those who have been ignoring Tidus or Wakka for the majority of the game. It relies primarily on two attacks. There is Aqua Shooter for magical/Water damage to a single character, hitting for about 300 damage.
The other is Depth Charges , which hits everyone for around 450 and can blind them for three turns. You’ll notice that Depth Charges are about to be fired when the obvious "Readying Depth Charges" message appears; next turn, they’ll fire, unless you cause 500 damage or Provoke the monster. (However, if Provoked, damage from Aqua Shooter is boosted by 50%!) The boss has a cyclical pattern from what I observed, using two Aqua Shooters before Depth Charges.
If possible, open this fight with both Slow on the boss, then Haste on yourself. After that, work up a simple brute-force offense with Tidus and Wakka, healing with Hi-Potions when the situation (
There are two alternative strategies. The first is pretty simple. You can avoid the Depth Charges if you Provoke the Extractor. As to whether to do this is up to you; personally, I don’t like this strategy. It boosts the damage from Aqua Shooter by 50%, making them almost as powerful as Depth Charges. Then again, Aqua Shooter is single, not multi, targeted. Plus, if you somehow have Water Ward armor, that can work really well.
The other pretty much requires the use of the Expert Sphere Grid and a lot of forethought. Had you started with an ESG game and backtracked from the start with either Tidus or Wakka to go along Lulu’s "path" of the Grid for her elemental spells and magic boosts, you could’ve gotten Thunder/Thundara by now and a nice bit of Magic to compensate. While neither character could really replace Lulu, it’s a thought for those ESG players who deviated from tradition, or just have no other strategy but to grind.
During the scene, you’ll get docked on the other side of the Moonflow. Stock up with O’aka and save first; that battle was probably taxing on your Eye Drops or Phoenix Downs if you were unprepared. Ascend the nearby incline to grab the Al Bhed Primer Vol. XII , then go west for an Ether .