Viruses are ubiquitous, found in every crevice on earth. Some, like SARS CoV 2, can end up killing their hosts. But researchers credit ancient viruses with helping us form long term memories. As parts of the world reopen for business, we consider how these little packets of genetic material are not just our enemy, but helped us to evolve. Viruses, it turns out, shaped our genome, and will like be part of our evolutionary future.