User blog comment:IamJakuhoRaikoben/Sorcerer Magazine, Issue 2: February 2012/@comment-3172403-20120301030400/@comment-4829046-20120301035315

Worry not Rai, I think once Natsu gains the ultimate meal he will become a humanoid dragon with scales, wings, tail and horns(mashima loves to do these kind of things., i know cause I have read EVERY SINGLE ONE of his manga)