The Mall or Department Store is the popular name of one area in Yume Nikki. It is a black-floored, purple-walled complex. It is full of people, but when interacted with, they only deform slightly and make odd rattling-hissing noises.
Its layout is rather strange. It has several pathways, rather like a maze, with walls facing diagonally. There is a second floor, but what is on it changes depending on how you enter it. One room - located to the far right of the map - is a small room with a large pool of blood on its right side. Two posters are on the wall, and it is populated only by a minute sort of pillar with limbs and eyes. When it is interacted with, it tips over, spilling blood onto the ground out of a hole in its head.
The flute effect is located here.