I think there is a misunderstander here.
Google "Super Mario bros nes" to see what "Super Mario Bros." is actually.
you have to hack
Big Boos have appeared in a multitude of Mario games. They first appeared in Super Mario World, released in 1990. They have since appeared in Super Mario 64, New Super Mario Bros. Wii, Super Mario Galaxy 2, Super Mario 3D Land, New Super Mario Bros. , and New Super Mario Bros. Wii U. They have also appeared in other series, like Mario Party, Yoshi, and Paper Mario.
The answer to your question is..... New Super Mario Bros.
its not there its in the ds one though
You can't. Unless there is a cheat out there, you can't be giant Mario.
It is down a tube so don't destroy them all as big Mario
Well, for new super Mario bros, then you have to have purchased a yellow toad house with 5 star coins. Go into it and jump on the "?" box.
There's a very large 'Big Boo' on World 2-Ghosthouse, of New Super Mario Bros 2.
You have to beat Bowser as mini Mario on the big castle on world 2 and 5!
you cant unless you a a gameshark with the code
You will probably need an action replay to do that. There is one code that lets you always have a Mega Mushroom. I'm sure there are probably other codes as well. You can buy action replays at places like Gamestop.
Keep collecting 8 coins until you get a MEGA MUSHROOM.