Sam, Dean and others in “Unfinished Business”

Sam

So Pestilence was spreading swine flu.

Dean

Yeah, but not just for giggles. That was step one. Step two is the vaccine. And you think...?

Crowley

I know. I'll stake my reputation that vaccine is chock full of Grade A, farm-fresh, Croatoan virus.

Sam

Simultaneous countrywide distribution. That's quite a plan.

Crowley

You don't get to be Horsemen for nothing. So you boys better stock up on... well, everything. This time next Thursday, we'll all be living in Zombieland.