People occasionally mention the horror inherent to fungi, and they aren't wrong in arriving in that kind of reading of our distant biological cousins, but I don't think viruses get enough attention?
Scraps of ancient viruses take up eight times more of the human genome than the coding genes that make humans human. Some essential functions in our cells were brought to us by viruses. It's debated whether viruses are even life or not. The same virus can infect some people for a lifetime with no ill effects, but kill others, sometimes for no clear reason, in days. Viruses defy our intuition constantly. They're not "fair" or "unfair".
