We don’t know what exactly this is, because there was barely a glimpse in the trailer. But, from what we saw, it looks like a firing ball. Apparently, the Robot, or some other entity in the movie has the ability to take different shapes. In one instance, it takes the shape of a huge ball and starts rolling along the road, simultaneously firing in all directions – cool; Might give engineers great ideas for the development of a combat machine that can fire in all directions when behind enemy lines.