I think the musical equivalent of it would be Diary of Dreams. The very darkest, very deepest part of who we are. Touching upon the central matters of existence, power(lessness), our very basic needs and fears... the essence of human nature, the nature of the connections we make with each other. Going beyond the superficial, the little distinctions and bits of information and everyday tasks. Going archetypal, it can never really be anything less than that. All our masks get stripped away in absolute darkness. Everything we consider to be ourselves, and yet at the same time we're more fully ourselves than ever, completely present. Not in a happy way. Just authentic. The way we're fully present and ourselves when we are facing something we fear. I think Whitley Strieber's "Communion" gives a pretty good feel of it. Tarot: Eight, Nine, and Ten of Swords.
Speaking of Diary of Dreams: here's an example of what I had in mind.