Swarms of demonically controlled metal monsters invade the streets of the city. They roar and scream and paw the ground, seeking the destruction of every living thing. They compete and jostle and collide, sometimes destroying each other in their reckless lust for human blood.
The toll mounts and the authorities, outnumbered hundreds to one, are helpless to stem the onslaught. The hideous spectacle strikes fear and revulsion into the heart of every rational being.
Those who value their lives take refuge where they can. They huddle in fear, and pray in silent despair for divine intervention to strike the monsters down and end the nightmare.

A new Stephen King novel? A bad science fiction scenario?

Nope, just holiday traffic here in the Metroplex.