He catches it. The twitch of lips. The crinkle in eyes that are expressive even at times when Cas is trying to be stoic. He catches hurt, and he latches onto it like a dog with a bone.

"Oh, I will. In about... twenty-five seconds." He's speaking to Kyle, but he doesn't take his eyes off of Castiel. He stalks forward slowly, eyes narrowing, scrutinizing the angel's face as the distance between them gradually disappears.

"We both know you can't do a goddamn thing about the Mark. You can't undo this. Even if you actually had the mojo, which you don't. You can fake your wings here all you want, but I can see you. I can see things I was completely blind to as a human. So, tell me something, Cas..." He slows to a stop about a foot away, black eyes flickering back to their old, familiar green. He could almost be mistaken for empathetic, bearing a striking resemblance to Concerned Dean Worried About His Friend — except there's a touch of mockery hiding behind it. "...Did you fall in love with me as soon as you slapped that hand print on my shoulder, or was it more of a slow build?"