Invasion?
So first off, I did not read the book.
Can someone explain how the aliens invaded in the first place? They're depicted as a glowing jellyfish that has to be handled with extreme gentleness and care, and then inserted through an incision in the back of the neck.
How did the first one accomplish this? I find it hard to believe that it snuck in in the middle of a spinal surgery, especially since it needs to be retrieved from its pod in the first place.
Is there an explanation for this? Or is this just a gaping backstory plot hole?