Because it was part of the plot? Why did you ask? It happens in Mario Galaxy though not Mario DS
get a power flower, and you can walk thru it.
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.
luigi's picture is in the lava fall in letha lava land inside the volcano in a secret room
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
This question is impossible to answer precisely, because there are several stars in cages in Super Mario 64 DS. Nonetheless, there are some useful tips when it comes to stars behind cages. Luigi can run through some kinds of cages if he grabs a Power Flower. Also, some cages can be opened by completing a specific task, like releasing the Chain Chomp in Bob-Omb Battlefield. What's more, some caged stars are accessible by finding a secret route which leads to the inside of the cage, like the slide in Tall Tall Mountain or the toxic maze in Hazy Maze Cave. Lastly, if all else fails, sometimes the name of a star will give you some kind of clue as to what you need to do, like "Luigi in the Cage" or "Mysterious Mountainside".
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
This one's a toughie. First, make sure you have 2 things done or gotten. 1. The presence of Luigi's caps (or much better, Luigi himself) 2. The power flower switch activated. Head to tick tock clock and find a Luigi cap. As you venture, you will find a cage with a star in it. The objective is to find a way to get inside the cage. I forgot where (I played this game 4 years ago) but there is a red block nearby the cage. 'Nuff said, you're Luigi, you're supposed to be invisible and able to pass through cages like this.
Not that I know of.