Castle Key (Tubba Blubba's Castle)
From the Super Mario Wiki, the Mario encyclopedia
The Castle Key is a name given to three different keys in Tubba Blubba's Castle in Paper Mario. The first is found in the basement. Mario goes left from the entrance, and takes a path in the north to access the north area of the basement. There is a yellow Boo in the basement and tells Mario about Tubba Blubba. This key allows Mario to access the right area of the castle. The second one is found in a spiky room on the second floor. Mario should hide with Bow to avoid the spikes. The third one is found in a room before Tubba Blubba's living room in the highest place. The room is guarded by many Clubbas.
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