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psychomanteum

alt. a mirrored room specially set up for communication with the spirit realm n. a mirrored room specially set up for communication with the spirit realm

Wikipedia
Psychomanteum

In parapsychology and spiritualism, a psychomanteum is a small, enclosed area set up with a comfortable chair, dim lighting, and a mirror angled so as not to reflect anything but darkness intended to communicate with spirits of the dead.