okay for that mystery gun, yeah i'm supposing its the new needler rifle, but the thing is I hear a targetting system starting up like the spartan laser, then I hear two percussive shots, followed by 4 impacts in the ground and also 4 explosions. So, I honestly have no idea, other than if, each shot splits into two, and is somehow able to have a delayed explosion even after hitting the ground. This weapon is very intriguing..could this be a human weapon? or the needler rifle.. hmm