@ZachWeinersmith regarding the reference: I'm not sure if this is the one you are looking for, but Tolstoy (yes, that one) wrote a story called "Esarhaddon, King of Assyria", where the namesake king experiences an entire life (not his own, though) as a mysterious old man is pouring a cup of water over his head - and wakes up when his other self is about to be executed to find that the water still has not fully run out. The main idea is "tat twam asi", "everything is you, and you are everything".