Seriously, why are you still playing that game?? (don't get me wrong, i am a hardcore mario fan.)
Super Dragon form does not exist in Super Mario World.
You have to complete the world five castle as mini mario.
if you mean new super Mario bros, then you beat world 6 castle when you are mini Mario.
beat the castle in world 1
it is not stars it is a world
In super mario? Ahem... You do all of the tasks before it.
All you have to do is go to the world 2 castle and beat the boss with mini Mario
It is very easy. Just defeat bowser in 1-castle.
Well, if you are talking about New Super Mario Bros. for DS, you go the final castle in world 5 where you fight Petey Pirhana. Well, the thing is that you need to defeat him WHILE you are mini Mario or Luigi.
For world 4 complete world 2 castle defeat the white thing being mini Mario and for world 7 do the same except on world 5 castle!
you beat the world 5 castle being tiny.
You avoid the Goombas and try to get a mushroom if availible