Freak out in the best way possible because Narnia. Invite him in, probably. Ask him how in the world he ended up in South Korea. If he was in fact very definitely an Earthman, I'd ask what he thought of the Topdwellers' world. If he wasn't an Earthman, I'd at least mention it later in the MLIN thread on here.
WWYDI you were offered a part in the cast/crew (scriptwriting, concept art, camera crew, soundmixing, actor/actress, etc., something withing your strengths) of the next Narnia movie after SC?