Terrans Will Integrate Us All!!!
What if Earth is the only planet with multicellular life? What if all alien life is unicellular and aliens are giant intelligent cells?
Then they encounter us humans, which, by alien standards, are a society of hive-minded societies of mindless cells. It would be as if all the hive-minded societies in sci-fi united into a super society.
Imagine their horror at the thought that cells are treated as mindless slaves. Having to obey orders blindly. I remember in my biology class that cells are sometimes ordered to kill themselves.
We would not be given the chance to interact with them. The moment they discover us, they will exterminate us in order to prevent multicellular life from spreading across the universe.
We would be worse than the Borg of Star Trek. We would be the megaborg.