Big Boo's Castle

Big Boo's Castle is the name of a supposed beta Big Boo's Haunt course. It is found in certain personalized copies of Super Mario 64. It is a clone of Princess Peach's Castle but edited to be Boo themed.

Star
There is often a singular star in this course known as "HUNT FOR THE BLACK VOID". Due to nobody finding a Black Void, there are close to no reports of what happens beyond this star.