At least, you're pretty sure it's a werewolf, since it landed as a man and blurred into the form of a wolf nearly six feet long as it rolls off your hood. You can hear it snarl and gnash its teeth threateningly at someone standing a few cars over to your left, then duck out of the way as a brilliant lance of fire streams overhead.

The other drivers seem stunned, but there's nowhere to move in this gridlock anyway. Some are getting out of their cars, but few seem to be running away; maybe they think it's some sort of show, and stand transfixed at the conflict.

[Dresden Files setting if you're familiar with it, be creative otherwise]