Dust (Editing Read if you wish)

"He looked ragged, his flannel shirt torn at the edges, jeans with holes. But he also looked beaten, like somebody had abused him mentally but not physically. Under his eyes were a purpleish pink color, a sign of no sleep. He was alert, looking for danger in every corner. Castiel had never seen Sam this worked up. He didn't understand. Until he saw what he was running from.

It was a menacing black cloud of smoke, swarmed around an even blacker object. It screamed, and Castiel thought he had gone deaf. It sounded like hundreds of people screaming all at once, only worse. It appeared to eat everything it touched, turning the green to black. Sky to grey."

The guy that owns Heavens Bakery shows up dead. He died a tragic death, but was it him that ended his life, or was it something else?