Morpha in The Legend Of Zelda: Ocarina Of Time.
Canonically causes multiple natural disasters, and is over both the most-infamous Dungeon and the most-popular Middle Boss.
Expectation? A Waterbender Cthulhu. Reality? …A glorified Blue Chuchu, just 1 attack, and can be cheesed in seconds.
Detective Pikachu Returns, Mario RPG 2023 and Wonder, whatever the new Peach one will be, and Luigi's Mansion: Dark Moon 2024.
But currently, I'm getting ready to buy Tears Of The Kingdom in the near-future.
Sombra throughout The Beginning Of The End, in spades.
Before? Tended to be more careful and serious than the other villains. Now? Suddenly a loud, reckless stereotype.