Luigi and Mario are friends, so it is unlikely that Luigi will kill Mario.
No
(The hey is wrong with you?) No, you cannot kill Luigi in Super Mario galaxy. (He's too precious)
The trick is kill Fake Luigi first, and it will make it about 100% easier. If you kill Fake Mario first, then Fake Luigi will give him a 1-Up Mushroom. Fake Mario does not have any 1-Up Mushrooms.
By defeating him in battle.
koopa troopas and luigi
Mario and Luigi are twins, but Mario is older.
luigi and Mario . luigi and Mario . lugi and Mario.
easy pals just kick him twice
Yes its Luigi.
There is no official answer, honestly. All we know is they are Mario and Luigi's "evil counterparts." well Mario and luigi are cousins and waluigi and luigi are brothers Mario and Luigi are brothers... and I highly doubt that Wario and Waluigi are cousins with Mario and Luigi.
Luigi is Mario's younger but taller brother.
Mario and Luigi are from Italy
You can only do it with Mario and Luigi. For Mario, press A. For Luigi, press B.