Thanks for the comment! The black (virus) blobs are randomly created and are more likely to be created the longer you play and the bigger you become.
I am aware that the game is in debug mode. When I built a version with it off, the game had several new bugs that I didn't know how to fix. So in the interest of time, I just released the debug mode. I think there are some more fundamental issues with the code that need to be fixed before I can turn off debug mode and get a performance boost.