Mario is the main character of Mario and the Search for the Inner Spaghetti Party Quest, and it is his job to find the Inner Spaghetti Party Quest, which is what the whole story is about. He is known to scream "MAMA MIA", which annoys people.
In the Prologue, Mario is kicked out of Peach's castle by she and Waluijew, who want Mario to earn his keep. He goes to see his friend Geromy and is advised to complete his Inner Spaghetti Party Quest after first being advised to complete the Inner Taco Party Quest. He then goes into the Desert to do some soul seeking. During this chapter, he is described as useless and fat by Peach. He does not know what a taco is at this point in time.
Mario enters the desert town not really knowing what to do. Because he had run out of water, he was forced to enter Casinoberg. He ends up in the Toad Inn, which was populated by toad skeletons, which was weird.
After having a nightmare about his Inner Spaghetti Party Quest, Luigi, Peach, and Daisy, Mario leaves the Toad Inn to go to a "spaghetti party with tacos" with Whoosh Whoosh Flappy and Waluijew. However, it is a trap, and Mario is captured by fat shyguys.