Paper Mario/Chapter 3: The "Invincible" Tubba Blubba

PEACH: Bowser's Little Helper
Sneak out as Peach, and you will find Kammy Koopa trying to tell Bowser that Mario managed to defeat Tubba Blubba. When they spot you, they will ask what Mario hates most. If you want starpoints say hard enemies, but on the other hand, if your low on items you can select those and later in the chapter you will find the items by treasure chests.

Boss: Tubba Blubba
Tubba Blubba is the third servant of Bowser to guard a Star Spirit. He is a big blue monster that is half Koopa, half frog, and half kangaroo. He is known as "invincible" to the Boos because he ate too much Boos and he was never beaten. He was shown in Paper Mario. He was first shown in Gusty Gulch getting ready to eat a Boo named Stanly.