Mr.B

Pikmin: Wrath of Mr. B
Mr. B created a huge army of mind-controlled bugs in order to take over Pikmin Planet and force pikmin to do his bidding. However, Olimar came to the pikmin's aid. Mr. B resided in a large abandoned machine of some sort (an old car), that he made into a fortress complete with traps and guards.

The Mother Dweevil
Eventually Olimar confronts Mr. B in his fortress. Filled with fury, Mr. B calls the Mother Dweevil to destroy Olimar and his pikmin friends. Details of the fight are found here

Mr. B Revealed
After his defeat, Mr. B is revealed in fact to be Louie, who developed the ability to control bugs with his mind and decided to use it so he wouldn't get pushed around anymore. He is then sent to Hocatote Federal Prison for his crimes.

Traits and Abilities

 * Mr. B can control all bugs on the Pikmin Planet. He tries to use this ability to take over Pikmin Planet, but Olimar stops him.

Pikspore
He the final boss.

Behind The Scenes

 * The "B" stands for "Bug".
 * Mr. B is derived from Mr. L.