ok was not expecting that to happen, now this raises soo many more questions about Natsu. Hope to god we get some answers soon enough.
could be some ancient old power sealed away inside Natsu that affects him from getting past the barrier(I hope this isn't the case, had enough of anicent old power hax being sealed away story>__<)
I somewhat see why Happy is called Happy, he's like fazed at first then gets past it extremely quickly lol. He is rather postive about almost everything