"Sorry, left my handbook for weird future Nazi cyborg limbs in my other pants," Tony snapped.

"Of course it was an accident. Why the hell would I--"

He stopped abruptly with a frown, for a moment no longer seeing Barnes or Rogers before he turned his head away completely, still caught in a thought process. Slowly his eyebrows lifted into something vaguely like horror, and when he spoke his voice was low, missing its usual sarcastic lilt.

"My god, it's your arm."