One of the toughest enemies (not really a boss) I ever faced was the Hydra in Grandia 3. He's not a particularly powerful boss, but one of its three heads casts a spell that causes all the heads to regenerates HP at an enormous rate whenever you aren't hitting them. The battle becomes a mixture of trying to cancel out the planned actions of the heads and using power moves to destroy the head with the healing ability. It takes quite a while to kill them all off.
What's worse... after you finish the fight and rotate the doors in the room, there's another Hydra waiting for you.
The Melc Crystal is also not fun. He is really one tough jerk who changes forms often. When he does, his speed is incredible and he has very devastating long range attacks that quickly decimate your HP.
PyTom wrote:
I have a confession to make. I am a munchkin. I will attempt to find loopholes in the game design, that make it trivial for me to win any battle.
A good example is Final Fantasy 9. One of the things with FF9 was that Haste stacked with Regen, which meant that a character with Haste would regenerate faster. Needless to say, I gave all my characters auto-haste and auto-regen (and maybe auto-cure, I forget). Over the course of the attack animation for the final boss (which involved slamming, IIRC, four planets into you), the party would regenerate all the damage from the last attack. The battle then degenerated into my party, not in any serious peril, repeatedly whacking the boss over the head with a sword.
I like to find loopholes, too. Again, in Grandia 3, give Yuki the "Berserk" ability and perform his special move "Flash" causes him to strike an enemy up to twelve times in a row. My roommate took it a step further and found that if you time it correctly with an aerial combo, you can get up to 30 hits on a single enemy.
So there is still lots of stuff in my games that I have never tried.