On your desktop. It’s an animation of a T4 bacteriophage eating through a cell wall. It’s like the creepy creatures in the Matrix, only more so because it seems to be covered with diamonds and emeralds, and because it’s as close as the scientists can get to reality.
I don’t know if it’s a “good guy” or a “bad guy” (“bacteriophage” sounds like something that eats bacteria), but anything that looks like a gastropod in the shape of a cell phone transmitter falls in the general category of “not sure I want it doing me any favors.”
What you don’t see (because it happens at the submicroscopic level) may or may not hurt you.