Present troops didn't stand a chance and got wiped out instantly. The White House got destroyed, no one survived - including the President of the United States, large parts of the administration, and several generals of the highest rank in the US Army.
Why we know that? Because we got it on f*cking camera! Strangely, tourists in the area were not attacked and could film everything. Those videos spread like wildfire on social media.
But the US was not alone: at the same time similar attacks were reported from Beijing, Moscow, Berlin, London, Tokyo, Paris - right down the top list of the most powerful countries on this planet.
Suddenly, every social media network, all websites, everything that was connected to the internet stopped working and displayed only one word: END.
We collectively freaked out. Even more so after the big darkness came over us: the power grid went down, and the internet with it.
And this makes sense, if you think about it. Arachnophobia, the fear of spiders, is one of the most common phobias - so why not model your foot soldiers in the image of a thing that makes the skin of your enemies crawl?
In addition to that, this form is able to move fast on any terrain and due to a broad variety of weapons absolutely deadly in most combat situations.