The Invisible Neighbor

I just recently decided, because the rear side is not shown in the illustration, I could go all crazy. So I looked up the internet for the rear side of tanks and found the image of a british Challenger 2.





The rear is much more detailed than the front, but in my opinion this is a good contrast. With the fuel tanks on its back indicating its Achilles tendon.
Apart from that there's also a tow rope and hook.

After all I've decided the robot to be about 3m tall for there is not a exact measure reference in Mauro's image.