The Wind Waker

Big Octo Guide:

With some relation to the Octoroks found in the Great Sea, the Big Octos are easily the largest enemies in the game. Fortunately defeating them is not too difficult, it's the locating them that's the hard part. The easiest way to locate them is to look for an unusual amount of seagulls in one area - about half a dozen or more. You have to sail directly underneath this flock in order to cause the Big Octo to rise.

-	A	B	C	D	E	F	G
1	-	-	-	-	-	12	-
2	-	-	-	-	-	-	-
3	-	-	12	-	-	8	-
4	-	-	-	-	-	-	-
5	-	-	-	-	8	-	-
6	8	-	-	-	-	-	-
7	-	-	-	4	-	-	-

Finding a flock is not very easy, especially on the water. You will need to make use of your telescope to find where these flocks are. Good places to look are Pirate Platforms or nearby islands. In fact, Old Man Ho Ho will even point one out for you on one of the islands. Beside is a table corresponding to the sea chart which you can use to find Big Octos. The numbers correspond to how many eyes the Big Octo has.

Defeating a Big Octo is not too difficult, the most effective weapon is the Boomerang, as you can target multiple eyes at once. The Bow and Arrow also is effective. Those looking for a real challenge can even use the Bomb Cannon. If you are eaten - don't worry. Apparently Link is not a tasty treat, as he will be spit out somewhere else. Once you defeat the Big Octo, they will leave behind a treasure chest, quite like the other kind you pull up with your Grappling Hook. As such it will require you to be in the exact position the Big Octo died. Below are the rewards for defeating each Big Octo.

4-Eyed Big Octo Location: D7 Reward: Great Fairy (doubles magic)	8-Eyed Big Octo Location: A6 Reward: 100 Rupees
8-Eyed Big Octo Location: E5 Reward: 100 Rupees	8-Eyed Big Octo Location: F3 Reward: 100 Rupees
12-Eyed Big Octo Location: C3 Reward: Heart Piece	12-Eyed Big Octo Location: F1 Reward: Heart Piece