Take a little bug or some small creature living hundreds of feet down a cave or somewhere similar or one of those little sea creatures that live miles down on the bottom of the sea, it is a fair assumption that they know nothing of us, of our lifestyles science art culture television cancer aeroplanes etc etc so I do not see how there cannot be the possibility that we do not know of a much more advanced species than us.
Hope that all made sense. after all the universe is a big place we might be no more than a school project experiment for an advanced beings science class.

Cheers

NCM