Yebbi

Yebbi is an important Nimbi in Super Paper Mario.

When Mario first encountered Yebbi, he actually had not seen him in person. Yebbi was afraid of the monsters invading The Overthere and decided to hide in a restroom. When Mario knocked, Yebbi asked who he was.

Mario told him what his name was, and Yebbi insisted it was ridiculous, and that he was a monster. They then told him he was a monster, and Yebbi still believed he was lying (meaning, he thought Mario wasn't a monster). He came out and relinquished the Yellow Orb, which was required to build a bridge to Grambi's castle.