Whose idea?

Did anybody ask whose idea it was to use the car as the dummy payload? I know Musk said earlier that they would use "the most ridiculous thing we can think of"; did he come up with the idea of shooting his car into space, or did some employee say, "Hey, boss, you aren't really using that sports car of yours much anymore, are you?"

Stephen Colbert's comment: "The launch was to demonstrate that the Falcon was not only reusable, but the Falcon Heavy can carry a large payload. So to test it, Elon Musk sent up his own Tesla convertible with a dummy astronaut at the wheel, blasting David Bowie's 'Life on Mars.' That's right, this is absolutely true—a giant phallus cranking rock 'n' roll, releasing a red convertible into the dark void. And the award for Most Midlife Crisis goes to Elon Musk."

I think it was pretty genius marketing. On a first test like this, nobody is going to put a multi-million dollar satellite in it; and definitely not a manned flight. Before the launch, Elon himself gave the launch a 50/50 shot at success. They needed something with mass, so why not take advantage of the opportunity?