Tuba Cat

The real Tuba King (Not to be confused with King Tuba I). Best friend and adoptive brother of the Tarantula Wizard. His trigger is easiest found nearby the area with the Walking Woods; in a patch of Midas Strain catnip. There should be a small key which you can unlock the room with.

The King Tuba I you meet in the Prologue is just a ploy for any potential foes like King Tuba II- who ended up killing his own father; the fake Tuba King; You can see hints of this when the false-king thinks nobody is watching the way he reveres the animal similar to the way Egyptians worshiped cats.

He's the last in the line of successors of the Tuba-Playing Housecat lineage; royal family predating the land of Orchestra and dating to around the end of the Era of Humanity; He's one of the few that have records of the Pre-Entropy; brought about by Tuborochi

https://www.youtube.com/watch?v=U-w4I5YCrUQ

Trivia

 * Interestingly, despite being a unique character and boss; there are actually several Tuba Cats in the game but they are called "Tubist Cats"; though the namesake Tuba Cat is also the only one with the unique Funk Machine. His name is also technically in error; leaving people to also call the original Tuba Cat "Sousafeline"- he even acknowledges in-game that a Sousaphone isn't really a Tuba but a Woodwind; but he sees that as a sign of goodwill between the Brass and Woodwind kingdoms.