The full prank call from a man impersonating David Koch here and here. There's plenty of pretty devastating moments. The Gonzo journalist who pulled this off just kept calling and somehow got through:
Ian Murphy: I called the number on their website. I kept calling that same number, getting a busy signal, waiting through 20 rings. That Koch would suffer such indignities made it extra ridiculous.
Mother Jones: Did you really think you'd get through?
IM: I couldn't believe it was that easy. Or why they wouldn't check around or something in between my calls. Or be competent. Or just not completely stupid. I blame it on the cheeseheads.
The raw partisanship and threats confirm to me that this is a classic piece of partisan warfare under the guise of fiscal conservatism. It also confirms every left-wing conspiracy theorist on the power of the Koch brothers. "Bring a baseball bat?"