You have to have purchased all of the other wallpapers that are available.
Get all the star coins.
A mini mushroom.
Blue mushrooms in New Super Mario Bros. make you small.
Use a mini mushroom (the tiny blue ones).
Mushroom, Invincibility (looks like a star), 1up mushroom (gives you an extra life), fire flower (let's you use fireballs), mini mushroom (shrinks mario/luigi), mega mushroom (makes mario/luigi grow to a huge amount), and blue shell.
It's called the Mini Mushroom.
You've got to either find a starman, a blue starman, or a mega mushroom and then you will be invincible for a while.
You get a blue house mushroom and you get to buy new walpapers for the bottom screen :)
You have to be Mini-Mario (tiny blue mushroom) as you fight the boss in world 2 (for world 4) and world 5 (for world 7)
You need to find a small blue mushroom, these shrink you so you can access secret areas via small pipes.
Blue shell solve my riddles and you will get the blue shell in new super Mario bros Ds. so pay attention. Riddle 1: It took so long for me to look for the blue shell. so i went to a shop with a mushroom coloured red......i have got the blue shell from the shop......What a discovery!!! as i ran with the blue shell wearing it helps me ram into goombas and koopas!! Riddle 2: As i started on a level i saw a Flying red block as i bumped on it it popped out a mushroom,fire flower, tiny blue mushroom, and a blue shell. Now take a note for what i just said!
You Need To Collect A Tiny Blue Mushroom which can be found In Some ? Boxes and Some mushroom men drop them
In order to become mini Mario or 'little Mario' in new super Mario bros ds, you simply have to eat a mini mushroom. These mushrooms are blue and very small, found in some of the games levels. The mini mushroom is also found in New super Mario bros wii.