Princess Peach's Castle/Castle Garden

The Castle Garden is a replacement of the Castle Courtyard found in some personalized copies of Super Mario 64. It is believed to be unlocked when a text box appears that states, "You feel the ground under you start to rumble... Princess Peach's Castle has changed!" (Demonstrated at the end of this video, appearing after 8 stars are collected in this instance.) It is also linked to another anomalous area, known as the Dark Room. It is showcased in this video.

Geography
The Castle Garden is a large open area, with very little to see. there are some trees and flower patches, as well as a road. It is surrounded by the same gray flooring as the Castle Courtyard. The path goes to the other side of the Castle Garden, with a split near the middle to the left, leading to the Dark Room. The middle path leads to a sign that says, "Feel the breeze of the wind and smell the flowers! Enjoy your time out here in the Castle Garden."

The Dark Room
The Dark Room is a large, black void, with the carpet and wall next to the door fading away at a certain point. There is a door seen on the other end of the Dark Room, with the same carpet and wall. In the center of the room is a small light with a Toad that says, "The Princess... and I...and, well, everybody...we're all trapped inside the castle walls. Mario, what are you doing here? Why are you wasting your time? We need to be saved. My bones are aching, stuffed inside of the Castle's walls. Get us out of here Mario... Please. Please don't let us die Mario." Walking into the other door crashes the game.