Do you mean Agent Smith? Or is there an Ovid quote I’m missing?

I'd like to share a revelation I've had during my time here. It came to me when I tried to classify your species. I realized that you're not actually mammals. Every mammal on this planet instinctively develops a natural equilibrium with their surrounding environment, but you humans do not. You move to another area, and you multiply, and you multiply, until every natural resource is consumed. The only way you can survive is to spread to another area. There is another organism on this planet that follows the same pattern. Do you know what it is? A virus. Human beings are a disease, a cancer of this planet. You are a plague, and we are the cure.

Nerdsnipe: The core of the quote is wrong. All mammals go through the same boom and bust cycles that other species do. There is no “instinctive equilibrium.”