User blog comment:Luffy1999/Top Strongest Characters/@comment-17726681-20130905225454/@comment-11310718-20130906062009

@Berserk333 Gon's body transformation isn't an ability, even he don't have an idea what was that and he haven't plan on growing up, i guess i could safely say, it was an effect due to the abnormal amount of nen, and besides, it destroyed his body afterwards, i think it was his Constraint and Vow  for example --- Gon : "hey ,my nen, if i can't bring kite back,please give me a large massive amount of aura enough to kill pitou, for that, i'll exchange my life,my body" Then what comes after that is beyond Gon's thinking and expectation,remember, he's just a rookie on nen. If you watch yuyu hakusho, it's like yusuke transforming evil when he defeated sensui, not similar but quite the same effect, or naruto having nine tails chakra whenever he's in some great emotional state like anger or something like that during a battle