The Gauntlet

The Gauntlet is an area in Challenge Node that Mario and Luigi can access. The Gauntlet is where the plumbers face X bosses, bosses they have battled before, but harder. The X bosses that can be fought in the Gauntlet are:
 * Durmite X
 * Biffidus X
 * Kretins X
 * Alpha Kretin X
 * Beta Kretin X
 * Wisdurm X
 * Magic Rod
 * Bowser Memory MLX
 * Junker X
 * Junker Can X
 * Dark Star X
 * Dark Satellmite X
 * All of the above plus Bowser X

Trivia

 * If the Bros. refuse to go into the Gauntlet, the Emoglobin at the door will mock the plumbers for being cowardly.
 * After beating the Dark Star in the Airway, the Emoglobin at the door will insist they train there for experience.