The unitive mystical experience can be compared to falling into a black hole. When compared this way, it doesn't sound like a nice experience. Likewise, for many mystics throughout history, their divine experiences weren't always a merry venture, sometimes encountering hellish realms along the way (see, for example, St. Teresa of Ávila, or St. John of the Cross's Dark Night of the Soul).
Fyodor Dostoevsky’s “First Vision” Account
Fyodor Dostoevsky (1821-1881) was a Russian novelist, writer, and philosopher. He often explored questions of psychology, philosophy, and religion. He wrote many acclaimed novels.
Joannes Stobaeus’ “First Vision” Account
Joannes Stobaeus was a 5th-century AD compiler of Greek texts in Stobi, Macedonia. He likely read widely, and recorded many of the most interesting passages he came across from Greek authors, including poets and prose writers. The following seems to be a reference to the ancient Mysteries, religious rites, secret ceremonies and initiations, and what took place in them, perhaps a reference to the Eleusinian Mysteries
He lays asleep, unknowing Black nothing Emptiness and nowhere No time, no space