Luigi is not in Super Mario 64 on the Nintendo 64, that was a rumor. However, on the ds version you can play as him along with Wario and Yoshi.
Because it was part of the plot? Why did you ask? It happens in Mario Galaxy though not Mario DS
Get 120 stars and talk to him and he will say something then you can use him!
When selecting your saved game with A, hold L and R buttons. You will play as Luigi.
Professor Egad isn't in the game.
You can't without cheating.
You can’t play as luigi in Super Mario 64! Because he is not in the game
There's no such thing as Luigi in Super Mario 64
No, luigi is not in SM64. You can only be him by hacking.
You can not unlock Luigi in super Mario 64 without hacks, but he is playable in super Mario 64 DS
Not that I know of.
you don't
You can't. No such thing.