I don't really know if anyone reads these things but i believe this is the only way i could think of to suggest this and i'm not even sure this is the right spot in the forum either.
As i happened upon the woods in the dead of night in Chernarus, i had heard a whitetail deer making their usual creepy sounds but it had struck me: i thought it would be a neat idea to add another infected that ONLY comes out at night and stalks only the wooded/tucked away areas and can be heard mocking animals to lure starving and desperate people in or making unique sounds and only being kept away by having your lights on at all times, not glowsticks but an actual source of light: Camp-fire, torches, gas lamps, flashlights, headlights etc while also being able to be killed like anything else in the game only...maybe a tad tougher?
Similar to spiders in one or more of the Metro games (not the actual spider itself but the idea of it being afraid of light and stalking the player). I can see how it would encourage positive interaction but also provide the opportunity for you to stalk other players while also being stalked keeping all parties on their toes or creates a strange tension like a Quentin Tarantino film mexican-standoff based on the factor of deciding if someone is even trustworthy or just for the time being. Several routes there.
I'm not entirely sure of this but maybe stun grenades/flashbangs stun this new infected? i thought about doing some "field research" and seeing if it was possible to stun animals in the game but i'm not sure why anyone would do that or if it proves useful at all.
Another thing: Where do they hide? perhaps caves and they group up in a herd/group like I Am Legend or maybe they go under the dirt like those face-clingers from Black Ops 2 Transit mode or maybe they just don't spawn until the pitch-black night. I'm not sure, simply a suggestion for the game or maybe as DLC. Let me know what you all think.