Warning: This article contains spoilers for Game of Thrones season 7 episode 6 'Beyond the Wall'.

Last night's (August 20) episode of Game of Thrones was pretty damn heart wrenching, though amid the epic battles and deaths, there was one very, very subtle detail that fans may have missed.

'Beyond the Wall' saw Jon Snow and his suicide squad do just as the title describes, heading into the wilderness as part of Jon's elaborate plan to capture a wight and present it to Cersei to prove the existence of the White Walkers.

In the ensuing battle with the undead, he calls upon the help of Daenerys and her dragons, though all our hearts stopped when one of them – Viserion – was killed by the Night King and subsequently turned into a zombie dragon.

At one point, however, it looked like Jon himself might have been a goner when he was dragged under water – though we know that was never going to happen, now did we?

Amid the chaos, one very fine detail may have been overlooked – a literal blink and you'll miss it moment, if you will.

As the King of the North emerges from the water, the shot focuses on his sword Longclaw's wolf-shaped hilt, the eyes seemingly opening as he pushes to the surface – as noticed by a keen-eyed Redditor.

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The sword, which originally belonged to House Mormont, was given to Jon by former Lord Commander Jeoh Mormont – in an earlier moment in the episode, he offers it to Jeoh's disgraced son Ser Jorah, who rejects it and that moment ties into a separate theory.

But what could this particular moment mean? Well, some on Reddit suggested it may be a future Bran warging into the sword to help save Jon. Hmm, that is very debatable, though sword-Bran likely contains more personality than actual Bran at the moment.

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Others suggested, however, that it may just be the effect of transparent crystal and subsequently nothing of note. Though going by the attention to detail the show tends puts in, we wouldn't be surprised if it signified something.

But the episode's director, Alan Taylor, has just completely crushed all hopes that Longclaw actually came to life.

He said fans were looking too much into it. "That is so funny," he told Insider."Somebody else mentioned that to me, and I haven't got a clue what they're talking about.

"So either this sword is magic and it's doing stuff on its own, or something happened. I'm going to have to go back and watch that moment close up and in slow motion to see what's going on there.

"I can say that there was no intention for that to be the case."

That's that, then.

Game of Thrones season seven concludes next Sunday (August 27) with a movie-length finale at 9pm on HBO in the US. It will be simulcast at 2am on Sky Atlantic on Monday (August 28) in the UK.

preview for Game of Thrones season 7 finale trailer
From: Digital Spy