[Phoenix Flame]

I saw a vid with a party (average level was 72) of two Bards, one White Mage and, umm... >< the party class that allows you to use 'Provoke.'

Basic strategy was to raise everyones defence with Protect/turtle shells, Haste the White Wizard (and everyone else using the Bards) and then blast away with harps while the 'Provoker' keeps the damage focused on him.

After a while the Iron Giant will begin using an attack that hits all of your party members for big damage - the person then began chucking Chocobo's Wrath at the poor Giant...who quickly fell. Great battle.