When you look into the light, then you are transported into a secret sky level that has a red button that unlocks the Wing Cap which can be found inside of red blocks with an exclamation mark on them. Once you press the button, a red box appears, and you must hit it and triple jump to fly into the air and collect all 8 red coins that are in the air to get a star. If you would like to exit the level without getting the star, then just fall over the edge and you will be transported back into the castle.
Once you have unklocked Mario and see the light change into Mario and look into the light with Mario- oh and its in the castle then youll be there.
if you are doing SM64DS go to the castle and look up into the light
Be Mario and go to the main lobby. Stand in the middle of the spot light and press x twice to be in perspective mode. Look up at the point where the light comes from and you will be taken to a secret level.
you have to look up at the light in the foyer of the castle and you will get wings and you will get power flowers if you step on the switch on the tower.
It takes you to another world
If you are talking about the sunlight on the carpet in the castle, you have to be Mario, walk in the light. Press X to center the camera behind Mario and look all the way up.......
Stand in the light on the carpet in the main hall of the castle, then press X and down on the direction keys.
Go with Mario (be sure to have him unlocked), beat first Bowser and get about 13 stars. Then, in the main castle hall, there should be a light shining on a spot at the floor. Stand on that spot and look to the light source. You'll warp into a secret level and Mario will get wings. Fly to the middle small tower and there is the switch. After pushing it, just fall down from the tower. You will appear in the castle again.
Castle Hill Light was created in 1890.
After obtaining at least 10 stars go to the main hallway in the castle (the one you reach when you enter the castle). You will notice a spotlight on the center. Stand in the spotlight as Mario and look up at the source of the light. To activate free looking press the 'X' button. You will then enter a new area wearing a winged cap (if you're Mario. If you're not you'll just fall down). Fly to the center of the level where you'll see a big switch. Jump on the switch to unlock blocks.
When a light appears in the castle and you look up (you have to be mario) and you will be flying around in a new level called hit the ! switch. Yoou collect 8 red coins to get a star and you hit the ! switch to turn the see through boxes into ! boxes where you can get wings and flowers.
At some point in the game, there is a shining light as soon as you walk into the castle. Then you look up at the light with the y button and look up at the roof. You have to be Mario though,you go to a special world and you are "Winged Mario". Then, there is a "?" button, you jump on it, and now, when you are Yoshi, there is a "?" block, you bust it open, and you got the fire flower!