The other day I was clearing debris from a fenceline. I turned over a rotten log to reveal a termite nest. I watched for a moment as the panicked insects scurried about with their larvae and such, then kicked their home aside and went about my business.
This is what First Contact will be like for us. If we're lucky. Note that I didn't bother to exterminate the critters.
Pound for pound, the amoeba is the most vicious animal on earth.