There's actually a very simple way to kill that new Game of Thrones enemy

Yes, it’s really happened. During recent episode Beyond the Wall, the White Walker head honcho launched an ice spear at dragon Viserion, plummeting Daenerys’ pet into an icy grave. And soon after the fire-breather was harpooned to death, the army of the dead dragged the dragon out of his freezing tomb to be resurrected by The Night King.

That flicker of Viserion’s frosty blue eye told the audience our worst fears had been realised: one of the Khaleesi’s dragons is now a wight and the White Walkers wield the Westerosi equivalent of a nuke. All the destructive wrath that tore apart the Lannister army previously in the season is in the hands of a now-unstoppable army of the dead.

But there’s just one problem with this plot twist: the wight dragon is incredibly vulnerable. Sure, an undead flying beast is bound to be an amazingly destructive monster, whether it unleashes a volley of flames or ice (we’ll have to wait to see exactly what powers Viserion has). Yet he’s still extremely exposed to either A) dragonglass, or B) any kind of fire.

Think about it: we know from Sam Tarly’s recent findings in the citadel that “dragonglass can destroy both White Walkers and their army” and in theory a wight dragon is still just a wight. So, to defeat Viserion all you need to do is load an arrow with a dragonglass point into one of Qyburn’s giant crossbows and voila! – bye bye scary ice zombie dragon.

But however simple that solution, it’s unlikely we’ll see it play out in the show: in the books dragonglass only kills White Walkers and wights can only be defeated with fire (we’re guessing this change in continuity was made to save the show from having to set too many wight stuntmen on fire). And although a wight dragon hasn’t yet appeared in the books, we think it’s a plot point George RR Martin told Thrones showrunners David B Weiss and David Benioff will occur in The Winds of Winter book (possibly out next year).

Yes, Weiss and Benioff have deviated from storylines in the novels – such as introducing the massacre of Hardhome – but a wight dragon is too significant a plotpoint to invent without Martin. So, presuming it appears in the book and it can’t be defeated by dragonglass, we probably won’t see villainous Viserion killed by dragonglass in the show.

Fire, though, that’s a different story. In both book and TV show, wights are moth-ball-level flammable. Time and time again, from season one’s wight in Castle Black to the reanimated corpse killed by Commander Mormont’s torch at the start of season three, we’ve seen that flames are no friends to army of the undead.

https://www.youtube.com/watch?v=M2TlSM-2SyI

And couldn’t the incendiary powers of Daenerys’ two remaining dragons easily set alight their new foe? How happy they’ll be to burn their brother to death or take to the skies when the Night King and his ice spears are below is another matter, but the point still stands: an undead dragon is far from unbeatable.

There might, just might, be hope for Westeros just yet.