From The Simulacra, by Philip K. Dick, 1964:
Something sizzled to the right of him. A commercial, made by Theodorus Nitz, the worst house of all, had attached itself to his car.
"Get off," he warned it. But the commercial, well-adhered, began to crawl, buffeted by the wind, toward the door and the entrance crack. It would soon have squeezed in and would be haranguing him in the cranky, garbagey fashion of the Nitz advertisements.
He could, as it came through the crack, kill it. It was alive, terribly mortal: the ad agencies, like nature, squandered hordes of them.
The commercial, flysized, began to buzz out its message as soon as it managed to force entry. "Say! Haven't you sometimes said to yourself, I'll bet other people in restaurants can see me! And you're puzzled as to what to do about this serious, baffling problem of being conspicuous, especially--"
Chic crushed it with his foot.
The above quote copied and pasted from a site that seems to rather miss Dick's point and thinks the fly is cool. (I may regret this link.)