Gogo is a mimic character from the Final Fantasy series. Gogo first appears as an optional boss in Final Fantasy V, and the players must figure out how to defeat him, as he is much stronger then all characters, and mimics their attacks, making it impossible to survive. The solution turns out to be doing nothing. Once the party has done nothing long enough, Gogo will be ecststatic, and grant the Mime class. The mime class is one of the most powerful classes in the game, granting two ability slots instead of one, making it very useful in the later stages of the game. It also grants characters the mimic ability.
In Final Fantasy VI, Gogo is a hidden optional party member. Upon traversing an optional dungeon, players can battle Gogo. If victorious, Gogo will join the party. Just like in FFV, Gogo simply mimics the actions of other characters.