Mysterious Mansion, as the name implies, is very mysterious. It is located near Haunted Port, and is considered to be the 8th sector. Mysterious Mansion is home to many weird stuff. Gravity Rooms, Morbid Mounds, and more is considered to be here. Many people from different Cartoon Universe Worlds come here on halloween to experience the Haunted-House feel. The U.S.F. came here to stop Herbert P. Bear from taking over Mysterious Mansion. There's even a haunted library in here! Very mysterious indeed.
- This is where the big episode Stickocolypse takes place.
- Mysterious Mansion is based off of the Haunted Mansion ride, the Lonesome Manor in Epic Mickey, the Matter Splatter segments in Smg, and all 5 mansions in the Luigi's Mansion sequel.