An enemy base is a special kind of a level. The player must traverse these bases in order to unlock the next world or level. Enemy Bases may be a Koopaling Castle, a Ghost House or a Fort.
Types of Enemy Bases
Koopaling Castles are the castles at the end of each world. Each Koopaling Castle houses a different Koopaling. Koopaling Castles also usually hold Doors, a Red Door, a Dragon Orb, a Suboss, and sometimes a Secret Exit. Koopaling Castles look like large stone towers with a sign with the World number next to it.
Ghost Houses are special levels filled with Boos. Big Boo will sometimes appear as a boss in Ghost Houses. Ghost Houses resemble wooden houses.
Forts are special levels that only appear three times. Forts usually contain multiple Doors and are mazelike. Forts usually end with a battle against Boom-Boom.