Switch Palace

Switch Palaces are levels in Super Mario World. They are special levels containing special switches that, when pressed, will unlock special blocks, similarly to Super Mario 64. There are 4 in the game, with a yellow switch, green switch, red switch, and a blue switch. Notably, these switches parallel the unused Yellow Cap Switch, the Metal Cap switch, the Wing Cap switch, and Vanish Cap switch respectively.

Super Mario 64 Manifestation
Switch Palaces have been reported to appear in Super Mario 64 in place of any cap switch level, and notably in place of other secret levels, most commonly the Princess' Secret Slide. These levels would appear similarly to the Switch Palaces from Super Mario World, with the cap switch they replace at the end (According to some reports, the replaced level's cap switch is put into another Switch Palace). Notably, when a Switch Palace replaces a secret level, the Yellow Cap Switch has been reported to appear at the end of the level. Notably, some people have reported the cap switch blocks having swapped caps, i.e. the Wing Cap being replaced with the Metal Cap.

It is believed that the Switch Palaces, similarly to the Cape Feather, are remnants of an earlier build of Super Mario 64 that was more similar to Super Mario World in nature, potentially Super Mario FX. However, some people theorize that the Personalization A.I. was given information related to Super Mario World to use in it's personalization. It is currently unknown why this would have been done, though some theorize this was performed in order to test the Personalization A.I.

Super Mario 64 DS Manifestation
In some personalized copies of Super Mario 64 DS, the Switch Palace can replace Tower of the Wing Cap. It usually appears very basic, being a large blue chamber with several walls and pillars with a ground similar in appearance to water. The ? Switch will be in the center next to a Power Star in most reports, but some say you need to run around to get 8 red coins or 5 Silver Stars to spawn it in this level. This level usually shares it's theme with Dire, Dire Docks or Hazy Maze Cave. The most notable aspect of the Switch Palace is that some have said that you can get warped to this area and obtain hidden stars that don't count as missions. This is likely the Personalization A.I. attempting to get past the mission count and add more stars.