Iron Giant (Final Fantasy III)

The Iron Giant is a hidden Superboss in the Nintendo DS remake of Final Fantasy III. It is hidden in the new dungeon under the sea. To battle it, the player must complete all the Mognet's sidequests, including the Ultima Weapon sidequest. It is the most powerful boss in the game.

Strategy
The most the Iron Giant does is attack, so casting Protect is really useful. Having Ribbons equipped comes in handy too, since his attacks may cause various status ailments. Other than that, the boss is not that much of a threat (considering it is a Superboss), except for its staggering 199,999 HP, its high Defense and the fact that it attacks four times per turn. Casting offensive magic and summoning may also help, since its Magic Defense is not so high. Another good tip, is to use the Onion Knight, if your party is already at level 91 and up since their stats skyrocket after this and they can use the most powerful weapons and armor and every magic in the game.

For the first half of the battle, Iron Giant will only use normal attacks, but once around half of his HP has been depleted, he will switch over to using the Slash/swipe attack, which hits all party members for 4,000 HP each, and casting Meteor on the party along with his regular attacks. Another popular strategy is to have all characters equipped with two shields in the back row, all casting their most powerful magic.