Princess Peach's Castle/Castle Crawlspace

The Castle Crawlspace is a floor of Princess Peach's Castle that can appear in personalized copies of Super Mario 64, as an alternative beginning floor. The Castle Crawlspace is accessed by crawling into a hole in the bottom of a wall on Princess Peach's Castle. The floor is a large maze, reusing textures from the Castle Basement, likely due to their similarities.

Related Phenomena
When the Castle Crawlspace is found, these 2 anomalies almost always appear:

Bob-omb Battlefield Displacement
Bob-omb Battlefield will be found in the Castle Grounds by walking through a path leading out of the level.

First Floor Lock
Similarly to Super Mario 64 DS, the First Floor will be unlocked. It will be unlocked when Bowser in the Freaky Forest, the Bowser level of the Castle Crawlspace, is completed.

Geography
The Castle Crawlspace is somewhat of a maze, which must be navigated by crawling. There are several rooms around that can contain Toads. There are other rooms with levels. These rooms are classified as follows:

Random Rooms
The Random Rooms are the names given to rooms with no particular use and some Toads scattered about.

Outer Garden
The Outer Garden is an area similar to the Castle Garden, that contains the painting of Ghastly Garden. Looking up towards the sky in this area leads to the Secret Sky.

Cracked Hallway
The Cracked Hallway is a hallwahy leading to Shipwreck Seas that has a crack in the floor leading to the Crawlspace Crack.

Flooded Room
The Flooded Room is a room submerged in water that contains the painting to Shipwreck Seas.

Castle Arcade
The Castle Arcade is a room styled like an arcade with several Toads scattered throughout. One arcade leads to Arcade Age.

Bowser's Cellar
Bowser's Cellar is the name given to a room accessed by falling through a trap door in a room disguised as a Random Room that has a room with a Bowser painting, leading to Bowser in the Freaky Forest.

The Lookout
The Lookout is an area that is one of the towers of Princess Peach's Castle. Looking out of the telescope aimed at the window leads to Sparkly Space.

Star Factory
The Star Factory is a hidden room that shows a conveyor belt moving along textureless stars that get painted to look like regular stars. It contains a Castle's Secret Star. It is found by punching a fake painting in Peach's Art Gallery. The implications of this area are unclear.

Peach's Art Gallery
Peach's Art Gallery is an area filled with paintings that cannot be entered, similarly to the Second Floor. There is a painting of Princess Peach, as well as a path up to the First Floor and Castle Basement, when they are unlocked. The Flip-Flop Facility painting is also here, as well as a blank spot on the wall with the shadow of a painting that leads to Shadow Cap in the Shady Sands. There are also 8 red coins scattered throughout the room that unlocks a Castle's Secret Star.

Shipwreck Seas
Main Article: Shipwreck Seas

Shipwreck Seas is an underwater course similar to Jolly Roger Bay.

Ghastly Garden
Main Article: Ghastly Garden

Ghastly Garden is a course similar to Big Boo's Haunt, but in a large garden.

Sparkly Space
Main Article: Sparkly Space

Sparkly Space is a large course that takes place on several asteroids in place, with some planets being able to be accessed.

Flip-Flop Facility
Main Article: Flip-Flop Facility

Flip-Flop Facility is a course with panels with specific icons that when touched, will flip a panel with an equivalent icon. It is a possible finished version of the unused Motos Factory level.

Arcade Age
Main Article: Arcade Age

Arcade Age is a course that is a recreation of World 1-1 from the original Super Mario Bros. with several edits.

Crawlspace Crack
Main Article: Crawlspace Crack

Crawlspace Crack is a level that is found near an alternate entrance to the room with Shipwreck Seas. It is a long rectangular area that must be climbed.

Secret Sky
Main Article: Secret Sky

Secret Sky is a level similar to Wing Mario Over the Rainbow and Tower of the Wing Cap, that would require the Wing Cap being unlocked to navigate.

Tip-Top Tower
Main Article: Tip-Top Tower

Tip-Top Tower is a level that takes place in the tower on top of Princess Peach's Castle.

Shadow Cap In The Shady Sands
Main Article: Shadow Cap

Shadow Cap in the Shady Sands is a Cap Switch course that unlocks the Shadow Cap, a cap that lets the player interact with certain shadows.

Bowser In The Freaky Forest
Main Article: Bowser in the Freaky Forest

Bowser in the Freaky Forest is the Bowser level of the Castle Crawlspace, taking place in a large forest.

Castle's Secret Stars
There are some Castle's Secret Stars scattered throughout this floor. These include:

Toad's Gift
This star is given by a Toad found in a Random Room.

Star Factory
This star is found in the hidden Star Factory room is a star just waiting to be collected.

Tree Climbing
This star is found on top of a tree in the Outer Garden.

Bowser's Cellar
This star is found behind a door in Bowser's Cellar, likely due to Bowser's Cellar being relatively hidden.

8 Red Coins In The Gallery
Peach's Art Gallery contains 8 red coins scattered throughout the area. When all 8 are collected, a star spawns in front of the Princess Peach Painting.

Theorizing
It is likely this level was removed after Super Mario 64 was downsized from 32 courses to 15, due to the amount of courses and levels in this floor rivaling other floors in the game. It also could have been removed to save cartridge space, as the map is quite large due to being a maze. The story also possibly could have been different, considering the Star Factory's implications.