I remember playing a PC game (Internet based I believe) between 5 and 10 years ago. I remember a black background and there were tons of little heads. I mainly remember the blue heads. Something about the green heads were poisonous or bad. I really don't remember much about the strategy of the game. There were stages and each one was harder. I just remember that it was highly addictive and everyone was playing it at the time. I know it's not much to go by, but hopefully somebody out there knows what I'm talking about.