Final Fantasy VI Boss 24: Storm Dragon
On the way through Zozo mountain to find Cyan, you'll find this guy, one of the 8 unsealed dragons. At level 34, this was the hardest boss I'd fought yet. Those wind attacks will pound the crap out of you, so you need to be healing on pretty much every turn, sometimes with two party members. Sabin's bum rush blitz is what won this battle. Otherwise, I'd have run out of MP to keep healing.
