'Green blob' thingy

[Cesca]

I'm still confused about the 'green blob' thing. So if the 'green blob' is not flashing in their eyepieces, what are they? An enhanced group of people (the enemies) or the survivors? Because there was this scene where Ben (Zombie) removed the implant from Ringer and then when she turned around, all that he has seen was just the flashing green blob, engulfing her head. Please explain this part.