Baby Luigi
Baby Luigi is a character in Nintendo's Mario series, similar to Baby Mario. He is the infant version of Luigi, although he has appeared in Mario Kart: Double Dash!! alongside his older self. It is generally accepted that these games do not have storylines and merely offer extra playable characters for greater variety. Baby Luigi first appeared in Super Mario World 2: Yoshi's Island where he got kidnapped by Kamek, only to be rescued by his brother Mario and Yoshi later on. Like his older self, Baby Luigi is voiced by Charles Martinet.
Baby Luigi more recently appeared in Yoshi Touch & Go, where Yoshi must rescue Luigi by throwing eggs in order to hit the Toadies carrying him. In the multiplayer mode, the second player's Yoshi will be carrying Baby Luigi instead of Baby Mario.
Baby Luigi rides along with Baby Mario in Mario Kart: Double Dash!! in a converted baby carriage and appears in Mario Superstar Baseball as unlockable character with speed ability.
Baby Luigi also stars in Mario & Luigi: Partners in Time, along with Baby Mario, his older self, and Mario. His abilities in battle appear to be identical to those of Baby Mario. The game explains the co-existence of the two sets of brothers in this game by saying that Mario and Luigi are sent back in time after an experiment with Princess Peach goes terribly wrong. They must battle the evil Princess Shroob to restore order to the shattered past of the Mushroom Kingdom.