I was thinking, if humans are at the early stages of nanotechnology, maybe the aliens have used this tech for some time... I mean, imagine the
possibilities! You could build an entire synthetic world that looked very real, well, if you had all materials that is

...
So, maybe these nanotech stuff they use are implemented in some places of the earth. And we still call them "curses", "magic", "ghosts" and
other occult things... who knows?