Reach the end of normal level 24, "Higher". Stand at the top left corner, just around the exit square. Drop down to your left to reach a platform. It is visible on the mini-map after you get close to the exit square. After landing, a large formation of blocks resembling the chicken from Toki Tori will appear. There is no way to get up again because the platform is also a checkpoint. You will not be able to complete the level and will have to restart.