Super Mario 64 DS/Goomboss Battle

After obtaining 8 stars, you will be able to open the door in the back of the Rec Room. There is a picture of Mario in the room behind it. Going inside will get you into the stage.

To reach Goomboss, you will need to reach the red X on the map.

To defeat Goomboss, you will need to run around behind him, then eat a Goomba that is running behind him. The, you can either spit it out or make an egg to hit Goomboss. It will take 3 hits to defeat him, but he gets faster with every hit. Upon defeating him, you will get the key to Mario's room, unlocking him.

There are 3 stars you can obtain in this level. There is a star switch, the 8 red coins and the secret star if you collect 100 coins.