User blog comment:TheCarrotSaysYumYum/Dragons, People and Demons.../@comment-3987368-20120721105325/@comment-3987368-20120724112315

You could be right. Igneel did supposedly place a spell on the scarf to prevent Zeref's magic from hurting Natsu. This magic spell on the scarf, having been cast by a dragon, may have prevented Natsu from exiting the barrier.

So Gajeel got pierced by his dragon? XD Well, people have been known to do weird things, though I'd personally though he'd just put them in himself or that they were maybe a side effect of his magic.