This week on Game of Thrones, the world shook, as Viserion, one of Daenerys' three beloved dragons, was murdered by the Night King and then resurrected with the bright blue eyes of his people. Though most creatures in this position would be called "wights," like the wight horses the White Walkers ride, or "undead" like the undead snow bear that attacked Thoros of Myr, Viserion is being called something else: an ice dragon. But what are Game of Thrones ice dragons? What do we know about them?
It might seem like the answer is "nothing, they're completely new," the truth is, they're not. In fact, George R.R. Martin, who wrote the A Song of Ice and Fire series has a children's book called The Ice Dragon, which he wrote long before A Game of Thrones. Published all the way back in 1980, it was set in a place that is clearly one of his earlier versions of the world of Westeros that we now know.
When it was republished in 2007, just before the Game of Thrones TV show went into development, it was treated by fans and publishers as part of the same world that the series is set in, though Martin himself is less strenuous about the connection.
The Ice Dragon story stars a little girl by the name of Adara who is born into the longest winter anyone can remember. She seems to be a bit of an other herself, with skin that is cold to the touch, no ability to laugh or smile, and a love of snow. She is best friends with an ice dragon that has been terrifying her town, taming it, and riding upon its back.
When fire dragons swoop in and attack her village, she rides out on her ice dragon friend to protect her family. Though there are multiple fire dragons, her ice dragon defeats them all before succumbing to his wounds and melting into a puddle, taking her frozen inner self with it and leaving her free to laugh and play like any other child.
Interesting data points here: a single ice dragon is able to take down multiple fire dragons. This suggests that Viserion's resurrected self may be stronger than his original, where he and Rhaegal are the beta dragons to Drogon's alpha.
This also jives with the legends of the ice dragons we hear in the actual A Song of Ice And Fire series. Ice dragons there reportedly roam the Shivering Sea — thousands of sailors have insisted on this over the years, though the maesters write them off. Part of the problem in proving their existence is that ice dragons supposedly melt when slain (see, also: the fate of the ice dragon in the short story). This would be a good thing for Jon and Dany to know before their armies face one.
Ice dragons are said to be bigger and stronger than the dragons of Valyria, with ice crystal wings and the big blue eyes that we saw open when Viserion was resurrected. Speaking of the blue eyes, there's also a constellation known as "the Ice Dragon," which is a little like our Little Dipper, in that it has a fixed star for various characters who find themselves beyond the Wall to guide themselves by -- the eye. Yes, it's blue.
Jon thinks of ice dragons a few times throughout the books, which he knows about from the tales that Old Nan told the Stark kids when they were growing up. One of the features of "Old Nan's Tales" is that they've all turned out to be true so far. I think the one that's now not far north of Eastwatch confirms that, too.
As to what the ice dragon breathes, ice or fire? That remains a mystery. Though I think we'll find out soon enough.