Editing Elder Princess Shroob

Finally, at the end of the game, after [[Princess Shroob]] is defeated, it is revealed that [[Princess Peach]] kept the center shard of the Cobalt Star. Peach tells the Mario Bros. that she cannot allow them to repair the Cobalt Star, but before she can explain why, [[Baby Bowser]] comes in and steals the last shard, combining it with the five that the heroes had already collected; the Shroob Princess, now enraged over the recent death of her younger sister, turns Baby Bowser into a [[Shroob mushroom]] and resumes her original form as Peach explains to the Mario Bros. what had really happened when she had gone back to that time period. Upon resuming her original form, the Elder Princess Shroob promises to kill the Bros. as revenge for her sister's death and then activates the platform they were standing on, engaging them in battle high above Shroob Castle. Notably, she says this in the language of the other characters, the only Shroob in the game who does that.

The Bros. manage to defeat Elder Princess Shroob and she becomes a Shroob mushroom, although not before gloating that even with her defeat, the Shroobs will ultimately best the Mushroom Kingdom regardless. Mario, Luigi, Baby Mario, and Baby Luigi take it to the present [[Peach's Castle]] for it to be analyzed by [[Professor E. Gadd]]. However, when they get there, they find [[Bowser]] lying unconscious on the floor. Suddenly, the Shroob mushroom comes to life and inserts itself inside Bowser's mouth, fusing with him to create [[Shrowser]] and reviving Elder Princess Shroob as a soul. The possessed Bowser regains consciousness and attacks the heroes under Elder Princess Shroob's command. Despite being unable to attack Shrowser directly, the heroes eventually defeat Shrowser, which in turn destroys Elder Princess Shroob's soul and eliminates the Shroob threat for good. The characters, after bidding farewell, then return to their own timelines.