Fairy Tail Transformation [Theory]
So with the new chapter 436 we know that Dragon Slayers can transform between humans and dragons as seen with Acnologia. Maybe if you have complete control over your Dragon Force and have mastered it you can change into a Dragon on command. In the near future we can expect to see Natsu turning into a dragon to fight with Acnologia once he has mastered his Dragon Force powers, this would also make a great fight of having two Dragons fight each other. Short and Simple.
Edit: Since Zeref and Mavis seem to know each other perhaps Mavis and Acno also know each other and even maybe Gajeel is somewhat related to Acnologia like how Natsu is related to Zeref and maybe Wendy is also related Mavis (not to sure about this pairing though) it could be possible with Gajeel since he couldn't pass Freeds runes either.
Posted May 19, 2015, 5:00 AM UTC · edited
we only know of acnologia having that power. and natsu thanks to the teaser image but not the other dragon slayers.
hence why I said those who have mastered Dragon Force sort of like Awakened DF powers. I mean when you go Dragon Force you gain features of Dragons so why not be able to go full Dragon mode?