Just as Mario & Luigi are cornered by Princess Shroob and several Shroob soldiers after the former removes her Peach disguise on the mothership, one of the Shroobs suddenly begins taking pictures before blasting the rest and their princess away with its blaster before revealing itself to be Kylie Koopa in disguise.
When Bowser attempts to kidnap the fake adult Peach, young Toadsworth comes charging at him riding atop baby Peach's carriage without hesitation, demanding he return the adult Peach at once. Also counts as a moment of funny due to the fact that baby Peach is in the carriage and is looking like she's having a blast.
The Mario Bros destroying the Shroob mothership.
There's something eerily awesome about entering the Koopaseum to find an army of Shroobs reveling in their tyranny. If you didn't already realize how much power and control the Shroobs had on the situation, that was the moment it clicked.
Mario sticking up for Luigi at the Star Temple gate, claiming it was the one lying and everyone was telling the truth, prompting it to realize its mistake and was only testing them.
Offscreen, but Peach using the Cobalt Star to trap Elder Princess Shroob. She may still get kidnapped by the younger Princess Shroob, but Peach didn’t go down without a fight and she managed to take out the strongest Shroob.
The fight against Bowser and Baby Bowser. It just feels so... right to defeat the duo.
The final battle against the Elder Princess Shroob. The two of you are on top of a floating platform high up in the sky, with the monarch attacking you with any minions and attacks that she can. Throughout the fight, Peach actively participates by giving the Mario Bros. stars to hit up to the Shroobs' ships and deal extra damage. Which is pretty cool by itself...then phase 2 kicks in where Princess Shroob transforms into a giant abomination that is so horrifying to look at that it makes Peach faint on sight.The music changes to a tense, almost sorrowful tune as this goes on. From then on, the princess does everything she can to eliminate her four opponents, including firing at her own minions, who gladly line up to be slaughtered and kamikaze the Bros. This fight doesn't even feel like it's from a Mario game; it legitimately feels like the Mushroom Kingdom's present and future hinge on this one encounter, making it all the more triumphant when you finally bring the tyrant down.
Then afterwards, a Princess Shroob-possessed Bowser tries to take the Bros. down with a constant barrage of attacks that leave the Bros. with no time to directly fight back. So what do they do? They send his attacks right back at him, whether it be by dodging them or hammering them back. That's right, the Mario Bros. defeated Bowser without so much as laying a finger on him!
From then on, the princess does everything she can to eliminate her four opponents, including firing at her own minions, who gladly line up to be slaughtered and kamikaze the Bros. This fight doesn't even feel like it's from a Mario game; it legitimately feels like the Mushroom Kingdom's present and future hinge on this one encounter, making it all the more triumphant when you finally bring the tyrant down.