Virus, one of the most interesting organism/half-organism ever on Earth.
It is here for one and only one reason, to replicate itself endlessly.
It does not respire, does not metabolise outside of a host cell, and needs a host cell to reproduce.
It can be crystallised and it assembles more copies of itself from materials within the host cell.
Megavirus chilensis is the largest virus to date and it too shows all of the properties above, but instead of hijacking the nucleus of the host cell to assemble more viruses, it encodes its own DNA to assemble more copies.
No wonder so many sci-fis are using virus in their main storyline. Creepy little thing.
