Well I'm honestly not sure about 'super dragon', but I do know how to make Yoshi breathe fire, if that's what you want, be Yoshi, go under a Red '?' box, jump, and once Yoshi gets the flower he can...
Well, actually you start out as Yoshi. If you mean, "How do you switch back into Yoshi?" then go into the door that corresponds to your character. For example if you want to Yoshi but you are Mario...
First you get all 120 stars then go to the pond outside on that pad there. there will be a cannon. aim yourself a little higher than the roof where yoshi is. you should find yourself there with a few...
Yoshi- Start adventure mode, skip the story and you get him Mario- get 8 stars, go into the top floor, go to the door that has 8 stars on it, and then go and dodge the enemies, and then beat...