How now, brown cloud?

Dan Froomkin wonders if we'll have have an answer for the mystery wrapped in enigma that is Cheney... or is that wrapped in "brown cloud"?

"'Judy Keen: You must be well aware of the caricature of you that has evolved over the last three years, the whole undisclosed location thing, the sinister force behind the President's policies. What do you make of that? And do you feel compelled to deal with it, especially in the context of this campaign that's just beginning? . . .

'Cheney: Why do I want to deal with it? What's wrong with my image? . . . Am I brown cloud? Am I the evil genius in the corner that nobody ever sees come out of his hole? It's a nice way to operate, actually.'

We never figured out what Cheney meant by 'brown cloud.' But now I wonder: Is that what he disappears into?"