Princess Peach's Castle/Peaceful Grounds

The Peaceful Grounds is an anomalous castle area found in some personalized copies of Super Mario 64. It is reportedly accessed by finding a hole or pipe in the Castle Grounds that will lead to the Peaceful Grounds or an area that will lead to the Peaceful Grounds. The Peaceful Grounds itself takes the appearance of a garden area that branches off to several paths and several levels.

Geography
The Peaceful Grounds is usually described as a round, outside area with some paths branching off. There are commonly several Toads and Bob-omb Buddies that can explain the levels accessed from the Peaceful Grounds, the Peaceful Grounds itself, and/or the story of Super Mario 64. The Dancing Flowers can supposedly also appear in the Peaceful Grounds, though this is unconfirmed.

Lower Level
The lower level of the Peaceful Grounds takes a similar appearance to the Basement of Princess Peach's Castle, with very little light making it hard to navigate. There is supposedly a power star that can appear in this area, though no evidence of this has been captured except for the video first documenting the Peaceful Grounds where a Bob-omb Buddy claims Bowser hid a "powerful treasure" in this area. The Haunted Ship level can reportedly be found in this area as well.

Peaceful Garden
The Peaceful Garden is a level usually accessed from the Peaceful Grounds by entering a tunnel somewhere in the area. The Peaceful Garden usually resembles the Peaceful Grounds, though is larger and more open. There are only 2 stars reported in this level, one hidden somewhere in the level and one from obtaining 8 red coins. Enemies reported in this level are Goombas, Whomps, Piranha Plants and Thwomps.

The Castle in the Sun
Not to be confused with the anomalous The Sun level, the Castle in the Sun is usually accessed by entering a doorway or painting in the Peaceful Grounds. It takes the appearance of a large tower in the sky surrounded by clouds and floating islands. The level is usually traversed using the Wing Cap and cannons scattered throughout the level. The only reported star is obtained by defeating King Whomp. The reported enemies are Goombas, Whomps, Thwomps, and Chuckyas.

The Haunted Ship
The Haunted Ship, not to be confused with the unused floating ship object in Jolly Roger Bay, is a level found in the Peaceful Grounds that can reportedly be accessed by using a door, painting or finding it in the lower level of the area. It usually takes a similar appearance to Big Boo's Haunt and the sub-area of Jolly Roger Bay inside of the sunken ship, though it is usually much larger. The only documented stars are obtained by collecting 5 secrets, and defeating a Big Boo.

Positive Emotional Aura
Similarly to the anomalous Flower Fields level, several people have reported a positive emotional aura being present in the Peaceful Grounds, as well as the Peaceful Garden. The Positive Emotional Aura seems to primarily be the design and theme of the areas, as well as the music. This may be the inspiration for the name of the Peaceful Grounds and Peaceful Garden.

Report 1
2 videos were submitted to the MIPS Hole Youtube channel by user BlackJoystick documenting the Peaceful Grounds for the first time. One was accepted, though the second one was yet to be uploaded. The first video, which can be found here, begins with BlackJoystick in the Castle Grounds, eventually finding a hole in the ground leading to a cave with a yellow pipe that then leads to the Peaceful Grounds.

The player talks to the Toads and Bob-omb Buddy in the level, and oddly, there is also a Bob-omb that appears to be a reskinned Bob-omb. After exploring, they enter the Peaceful Garden level. There, they collect the 8 red coins and then the star spawned by the red coins. They then go to a part of the Peaceful Grounds with a blank sign, enters the doorway next to it, and the video then ends. However, they later return to the Peaceful Grounds to explore the Castle in the Sun level in the second video, which can be found here. In this video, BlackJoystick starts in the Peaceful Grounds, before entering the doors leading to the Castle in the Sun and warping to the level. They talk to a Bob-omb who claims that Bowser sent King Whomp to the level in order to take over the Castle in the Sun, and take the power star. BlackJoystick then explores the level, before walking into a power star that warps them to another part of the level. They then climb up the path they are teleported to, before talking to a Bob-omb Buddy who claims they set up a cannon for the player.

BlackJoystick collects a Wing Cap, and then uses the cannon to fly to some clouds, which lead to the top of the level after flying from cloud to cloud. They then enter a door leading to the area where they get to fight King Whomp. King Whomp talks about their defeat in Whomp's Fortress, before fighting the player. The player then defeats King Whomp, who drops a star, which interestingly appears to already have been collected, implying that BlackJoystick played this level before recording it. They then briefly attempt to enter some doors in the area before collecting the star, causing the video to end.

It is believed that there will be a third video either exploring the lower level of the Peaceful Grounds or the Haunted Ship. However, BlackJoystick has not confirmed or denied this potential third video though did claim before the second video they wanted to make more videos on it, so it is likely the third video will be created.