@blue-case90
Every Kingdom Hearts game has at least 1-3 of them (aside from Re:Chain of Memories, but nobody fucking likes that game). They tend to be the kind of superbosses that you only fight if you’re a masochist, but there are a few that are actually really fun to fight (the ones against Sephiroth in 2 and Data Xigbar in 3 come to mind).
That being said, fuck the Unknown in Birth by Sleep. I know I’ve complained about the Data Battles in 3 recently, but those at least seem beatable (if only BARELY). But the Unknown doesn’t want to be beaten. He just wants to shank you, and then make off with your live savings (i.e. he’s SNK levels of bullshit).