Dreamy Pi'illo Castle
From the Super Mario Wiki
Dreamy Pi'illo Castle is the Dream World's version of Pi'illo Castle and a location in Mario & Luigi: Dream Team. It is the first location visited in the Dream World. On Mario's first visit, he meets Dreamy Luigi for the first time, Prince Dreambert is rescued and Antasma summons Dreamy Mario to battle the brothers. This is also the location where Peach is first kidnapped.
After Peach is again kidnapped by Bowser at Driftwood Shore, the heroes return after hearing there may be an alternate entrance to Dream's Deep, which proves to be right as it's behind a door which can't be enter the first time and is where they find a huge Zeekeeper statue and get the Ultibed instructions in the form of a manual/pamphlet.
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