Is this real or sarcasm about how people take every word, no matter how minor, as foreshadowing? I mean, you could also argue that the Brain in the Jar people are proof the Mi-Go exist in the Dresden Files, and that their abductees have rebelled and are conspiring with the people of the Inner Earth (which also exists) to overthrow normal humanity.
Totally real. Jim does this kind of thing all the time. Even some of his book titles give away the plot, and you cannot know until you read the book. Like Skin Game. It isn't until the end where Goodman Grey, a shape shifter was actually working for Harry, and not Nicodemus.
Or the Lightsaber mention, and then Butters ends up with a virtual Lightsaber in a future book.
The psychic jellyfish sounds exactly like Nemesis in my mind. I can just imagine it's long invisible tentacles reaching out, and ensnaring it's prey.
I'll add that Jim has said that he's dropped hints in his books that you cannot understand until rereading them with the knowledge of future books.
