[spoiler]Jake pulling an Alloran and flushing 17,000 naked Yeerks into space.
To get the Andalites to allow morphing cubes to be used to morph Taxxons and Yeerks into harmless nothlit forms, Ax (with the support of the newly freed War-Prince Alloran) challenging an Andalite Prince to a duel!
In the aftermath of the defeat of the Yeerks, Andalite tourists coming to Earth, morphing human, and eating everything in sight!
Marco becoming a supporting actor, using his Animorph powers to play a hero who turns into animals!
Jake, Tobias, and Marco going off on an unauthorized mission to rescue Ax, who has apparently been taken captive by aliens in league with a rouge Yeerk Blade ship.
The final words of the book: "Ram the Blade ship" (on which Ax has been taken over by "The One").[/spoiler]