Um for me I have to go way back to the Game Cube for that boss. It was Paper Mario: The Thousand Year Door. Ugh I dont remeber the actuall nam e but the Finmal boss where you have to face Dark Peach, espesically because you have to face i think 2 bosses before you get to her. I have yet to beat that game. And also in that game the boss at the end off the the 100 something trail (I don't remeber the name it was like 2 years ago that I played that game) but still I only got to him once and I had low HP and he kicked my arse.