Kirby Super Star Cheats

On the level select screen in Milky Way Wishes, move kirby to the green star between Cavios and Skyhigh, and then enter the level. Here you can find the Copy ability.

If you use the Stone ability enough, you may turn into a statue of Samus, or a golden statue of Mario.

In Megaton Punch, if you look in the background, you'll see Mario, Luigi, and a few other people from the older mario games.