"We can't," Sam dares to speak. "Not yet," he hastily amends, once Death has gifted him with A Look, and Bobby pipes up that they need him to kill God. "What makes you think I can do that?" Death eyebrows. "You told me," Dean reminds him. Death eyes him for a very long moment, then inquires, "Why should I?" "Because we're the boss of you?" Dean hesitantly replies. "Amazing!" the just-appearing Castiel breathes from another corner of the room, and oof. My Godly Baboo's not looking so hot, here. That rash now seems to be slowly eating away at the flesh around his eyes, and lurid streaks of red have spread out to cover most of his face. Castiel rises above, however, and promptly vows to slaughter them all with a simple snap of his fingers, but Dean helpfully points out for the audience's benefit that because he and his compatriots have shackled Death, the three are, for all intents and purposes, immortal. This clearly throws My Godly Baboo for a loop, but before we get a chance to dwell on that for too long, Death leaps in to kick-start this evening's heaviest bout of exposition, and the upshot of it all is this: That rash spreading across My Godly Baboo's sweet little face? Merely the external manifestation of the havoc Purgatory's millions are now wreaking upon his Vessel's form. "You're going to explode," Death knowingly predicts, and that wouldn't be so much of a problem for anyone were it not for the fact that Castiel inhaled some Very, Very Bad Things at the end of the last season's finale. Specifically, "The Leviathans," whom Death defines as the real God's "first beasts," creatures who predate everything else in the real God's creation including the angels. "I, personally, found them entertaining," Death admits, "but He was concerned they'd chomp the entire Petri dish, so he locked them away." "Why do you think He created Purgatory?" Death rhetorically wonders, pointedly directing this at Castiel. "To keep those clever, poisonous things out," he continues before emphasizing, "And now, Castiel has swallowed them -- he's the one, thin membrane between The Old Ones and your home." Dun-dun-DUN!