The Final Fantasy series has a long history of featuring insanely difficult boss battles that soak damage like a sponge and shrug off attacks as if they were being bitten by a gnat, but Final Fantasy XI has some of the most sadistic bosses of any main entry since its conception. Why it's unfair: Pandemonium Warden isn't just notorious among fans who have had the displeasure of coming up against him. The boss made headlines across the world when it appeared in the first Final Fantasy MMORPG, and not for good reason. A group of players, eager to test their mettle against the Warden and to be the first group to beat it, spent 18 concurrent hours attempting to defeat it without success. After the group's members started fainting and vomiting due to fatigue, Square Enix was forced to significantly reduce its difficulty. Today though, it's still laughably unfair. Pandemonium Warden has ten different forms you need to get through before you can call yourself a 'winner', but honestly - regardless of who emerges victorious, nobody is a winner in this unfair fight designed only to test your patience.