Nietzsche's believed in Eternal Recurrence.
That time and the universe is infinite, so everything that happens or can happen has already happened an infinite amount of times, and will happen again an infinite amount of times.
That an infinite number of identical Nietzsches existed doing and thinking exactly the same thing as he, in identical worlds, and would do so yet again.
Eternal Recurrence was his final theory before he went insane.
Being John Malkovich. Everything becomes Malkovich... That'd about do it...