It all depends on the version,
For Land, definitely Captain Syrup C:) and this old fuck DrStein:
For Ware, easily Jimmy :jimmy: and Mona :monapizza:
For the Mario Sports games, I gotta go with this trio
Don't even get me started! By far the most broken boss in the game.
Those giant Luigi sections were cool the first time, but playing it again in hardmode, was way more work than fun