Dog Catcher Trophy in Archangel

I'm not great with enemy types thrown at me during combat so I had thought that a stalker was a different enemy type than it is. Thus I spent the first 3 missions punching, and amusing my wife, for no reason. Once you get to mission 4, I think, you'll head down into a ravine with some fog. You'll get to some dog-esque robots, these are your target. You can shoot them but when they leap at you you'll get a chance to punch them. You'll need to actually kill them in order to get the trophy so if you shoot them too much you might kill them before you get a chance.