From the Super Mario Wiki
Retrieved from "http://www.mariowiki.com/index.php?title=Safari_Room&oldid=2003832"
After Luigi uses his Poltergust 3000 at each of the mounted deer heads on the north wall, a Blue Blaze appears. After Luigi defeats it, two others appear, along with two Garbage Can Ghosts. After defeating all those ghosts, a chest that has a key inside will appear. This key opens the door to the Area 3 boss: Boolossus.
The Safari Room has three animal pelts on the floor (and only two pelts on tables in a pre-release version). It also contains two shelves of boxes under the deer heads, as well as an easy chair on the east wall. Beside the easy chair is a chest that always contains a 50-HP restoring Heart for Luigi. There is a piece of cheese that contains a Gold Mouse wedged between the easy chair and the chest. Using the Game Boy Horror, the player can see a mirror on the south wall that can be used to teleport back to the Foyer.
Ghosts in the Safari Room in the PAL Hidden Mansion
Ghosts in the Safari Room
Ghosts in the Safari Room during the blackout