Paper Luigi

Paper Luigi is a paper incarnation of Luigi that came out of a magical book in Mario & Luigi: Paper Jam. Paper Luigi is an independent character from Luigi and only appears after the player unlocks the music player after beating Shiny RoboBowser. He appears to sleep in Twinsy Tropics while Mario, Luigi, and Paper Mario are on their adventure. Luigi himself was previously depicted in Paper form in the Paper Mario series games, but there is no indication that those games took place within the book and involved the separate Paper Luigi character introduced in Mario & Luigi: Paper Jam.

Trivia

 * Paper Luigi was planned to be playable in Mario & Luigi: Paper Jam but was taken out due to the fact that it would be too difficult to control four characters.