A very good surmise. Several years ago, I had a dream that featured Christ, Nietzsche, Satan, Superman and my grandmother. On the beach. Who wrote that?
haha, wow, you have some unique dreams. Who's the author? Well, Nietzsche's there...Nietzsche wrote the Anti-Christ, and the anti-christ is traditionally affiliated with Satan...and of course Nietzsche is famous for his talk of the ubermensch, often translated as the Superman. Nietzsche also, I believe, spent lots of time "recouperating" on the beach. And your grandmother's presence? Maybe you were trying to channel Nietzsche and she was there to put a stop to it.