Bogie Mares Case Mystery Cache

If humans were to discover life elsewhere in the universe it could end up being a virus. They massively outnumber other species on our own planet and are relatively simple chemically--little more than genetic material encapsulated in a protein shell and a durable lipid envelope. It's even possible the viruses we encounter on earth are the ancestors of alien invaders from long ago.

Though it's debatable whether viruses should even be counted as living things. They lack the replication mechanisms found in other lifeforms and must hijack the machinery of a host cell in order to translate their DNA into polypeptides.

Viruses can, however, be difficult to detect, even on earth. Seeing as they are not independently active they produce few by-products when they're not replicating themselves in a host cell. And given the diversity of virus forms on Earth alone, there's reason to doubt that we would detect an alien virus particle in outer space even if we did stumble on one. We could potentially make contact with an alien and not even recognise it, let alone have the intelligent exchange we seem to hope for!