uhhh...*strains to think*.....uhhh....Star Fox and LOZ bosses are weak........I'll probably say.....just forgot it......OH YEAH! The final boss of one of the Fire Emblem games. Better yet, I'll say Dark Knight from the GC Fire Emblem. He was owning me. The ifrst lvl you fight him, when he walks out of a building and you know from the start "I am so ****ed...."
Mine would have to be Ozma the optional boss from FF IX which I lost to 25 times then gave up to finally figure out a easy way to beat that I still haven't done.
I just saw a vid of some newbie fighting the Enigmatic Soldier in KH2:FM+ at level 60-something with the A Crossing Two Keychain. The player was absolutely ANNIHILATED in 2 hits. Guess that rules out beating him on a speedrun, and possibly not doing this to your manhood or even yourself: