If 3rd parties were never added to Smash I feel Muddy Mole would be in by now. Despite often being the butt of “literally who” jokes there’s no denying MM is one of the more well known one-off Nintendo franchises and, even if he’s not on the level of Isaac or Takamaru, Muddy support dwarfs other lesser known Nintendo franchises like Drill Dozer, Sutte Hakkun, Tin Star, and even some more relevant/active series like Fossil Fighters, Ever Oasis, and Sushi Striker.