Sushi is a character who appears in Mario Party Advance.
In Mario Party Advance[]
When the player's character first meets Sushi, he complains that someone has fallen off a cliff. The player is then given the choice to do the Sploosh! quest. Shroomlock suddenly makes an appearance, startling Sushi. In their discussion, Shroomlock reveals that someone had pulled him off Sushi Cliff. Although Sushi did not see this occur, he mentions that there were three witnesses to the crime: Blooper, Cheep Cheep, and Dolphin.
After going through each of the three witnesses' excuses that they were not responsible, with each one emphasizing a part of their body in their quote, Sushi and Shroomlock, with help from the player's character, conclude that Blooper is the only one capable of doing the crime because of his tentacles and being the only suspect who has appendages. After Blooper appears, both admitting and apologizing for committing the crime, Sushi is amazed that the player's character managed to solve the crime, and rewards them the Digitizer Gaddget.
In the ending, it is stated that Sushi decided to open a bed and breakfast at the sea.