I'm impatient so I'm going to tell my character idea anyway. Do you think that the inexperienced group would actually trust a very small virus that seemed benevolent and tame in every way? Sort of like their pet cookie embodied as a dog-like creature. It doesn't require much data to eat, thus only taking what is fed to it. When it is fed enough it makes a significant bodily change rather than a simple jump in size. Things like wings, a hard, shield-like shell or even human speech. 

I got this mainly because I don't feel like taking up a Mod spot with this many people. (And I still want in XD)