Ghost House

A small house in Super Mario World which is home to the Boos. Since you can save your game every time you complete one of these, you should go through them when you complete a hard level.

There's 6 Ghost Houses in Dinosaur Land: 2 in Donut Plains, and 1 in the Vanilla Dome, Forest of Illusion, Chocolate Island, and Valley of Bowser.

It is followed by Big Boo's Haunt in Super Mario 64 and in Super Mario Sunshine, on Sirena Beach is Hotel Delfino, which is considered to be the ghost house of Sunshine.