What do you do?

You look out across the desert and you see a large reddish-brown dog.
How large?
Easily 50 feet tall. It has goggley eyes with a hint of sickly yellow in the center. On the end of its tail is an enormous 8-ball, swinging around like a wrecking ball. It has a bright red collar. Instead of a tag, a giant pine air freshener, the size of a toolshed, swings from its neck.
What's it doing?
It trots down Route 666. Cars swerve out of its way. It growls at them, bends down and bites the road. It peels the pavement up off of the ground, like a strip of black licorice, and shakes it. Cars fly through the air and crash in dusty heaps of twisted metal. With chunks of asphalt dropping from between its teeth, it turns and looks at you. It seems to be smiling.
Smiling?
Sort of a mischievous grin. What do you do?

During the course of a game I ask the Players this question again and again: What do you do? It's their cue. They're on. It's their turn to be a hero, or die trying. That's what it's all about - what THEY do - the Players and their characters.

What they do needs to be left entirely up to them. It shouldn't be scripted. I've played in tons of games where the characters are being led through the story and nothing that they do seems to alter the story. I intentionally create situations for my Players that I don't have a solution to. I don't know how they're going to get out of the problem they've gotten into. This is usually when they come up with the most interesting solutions. If I spoon-feed them a solution, then they get through the adventure, but they don't always feel like they figured it out for themselves.

So, what do YOU do?