Baby Luigi

Baby Luigi is the young form of Luigi. His first game was a prequel to the Mario games, Super Mario World 2: Yoshi's Island where Kamek stole Baby Luigi, but missed Mario. When Yoshi caught Baby Mario, the two of them went out to rescue Baby Luigi and bring the two of them to there parents.

In Mario Kart: Double Dash!!, Baby Luigi, along with Baby Mario appeared as a playable character. They are in the Light category, and their Karts are buggies. Their special exclusive item is a Chain Chomp which allows them to go faster, plus ram through other racers as well.

Baby Luigi's most notable appearance is most likely Mario & Luigi: Partners in Time where Baby Mario and Baby Luigi, along with there older selves, were playable characters. They met up with there older selves while Mario and Luigi went through time to save Princess Peach.

SNES

 * Super Mario World 2: Yoshi's Island

GameCube

 * Mario Kart: Double Dash

GameBoy Advance

 * Yoshi's Island Advance

Nintendo DS

 * Mario & Luigi: Partners in Time
 * Yoshi Touch & Go
 * Yoshi's Island DS

Wii

 * Mario Kart Wii