If this Game of Thrones dragon theory is true, there could be absolute chaos in Westeros

Needless to say, this post contains spoilers for the latest season of Game of Thrones.

We've heard around 18 million Game of Thrones theories at this stage, some of them far more plausible than others, but all of them interesting. We've already had one theory from earlier seasons all but confirmed towards the end of last season and through many hints this season. We're of course talking about the well known; R + L = J. This latest theory is a bit more of stretch, and as we approach the end of the current season, it's to do with how the show will end. A theory which has begun doing the rounds in recent times involves Daenerys, her dragons and the Night King... and his dragons. The theory has stemmed from people who have been rereading George R.R. Martin's books for clues about what lurks in the final battle. So what are the clues? First of which is the fact that Martin wrote a book 16 years before Game of Thrones called The Ice Dragon. Also in the books, Old Nan, who was previously correct about direwolves and giants, says the line “cold as the breath of the ice dragon." Although in the series, Robb Stark says that Old Nan told him the sky is blue because they live in the eye of a blue-eyed giant named Macumber, so maybe she's not the most reliable source. In the books, the ice dragons are described by Maester Margate in The World of Ice and Fire. He goes into detail about, "Colossal beasts, many times larger than the dragons of Valyria... said to be made of living ice, with eyes of pale blue crystal and vast translucent wings through which the moon and stars can be glimpsed as they wheel across the sky. "Whereas common dragons (if any dragon can truly be said to be common) breathe flame, ice dragons supposedly breathe cold, a chill so terrible that it can freeze a man solid in half a heartbeat." People are speculating that the Night King may have an ice dragon hidden north of the wall, or another more popular theory, suggests that he managed/will manage to resurrect one. With Bronn coming close to killing one this season already, it's not beyond the bounds of possibility that at least one of Daenerys dragons will die at some stage before the show finishes.