[ cas isn't great about beating around the bush of his concerns, or skipping out on honesty (when it isn't misdirecting from a horrible bad no good mistake he's recently made), so the answer comes out simple and frank. ]

I've gone full human, without the aid of a transdimensional pillar of creation.

[ so, yeah, seems like that could definitely happen. his goal wasn't to freak dean out, but here we are. ]

Which means we can turn you back into a human.

[ probably not the kind of reassurance dean was looking for. ]

There's worse things you could be turning into?