Go to stage four and collect 50 or more rings. Press A, B, and C at the same time. The music will change. You will be a golden Yellow and twice as fast. You can jump twice as high too. I would collect 70 rings if I were you. Once you use this code, every 1 or 2 seconds makes you lose a ring. When you lose all of your rings or beat the boss to go to Act 2, you will become normal again.