"You left your...skin in Portland." Rhys has no idea what Portland is but that's not the big thing here. The big thing is that his skin is apparently detachable and can be left in places. Maybe it's the case of shedding or molting or whatever sometimes happens on Pandora when you step on something you think is an animal, scream for a few minutes, only to realize it's just skin?

Maybe it's like that.

"So, what are you?" Rhys asks, not even realizing how rude and insensitive a question that is. The filter between brain and mouth is there but Rhys uses it so infrequently.