Still having nightmares about that bit in the Game of Thrones season 8 premiere when little Ned Umber's dead body, which was pinned against a bunch of severed limbs, suddenly woke up and started screaming? Us too.
You may also have lost a few hours' sleep wondering why the disembodied parts were arranged into a lovely spiral pattern by the White Walkers.
Well, the premiere's writer Dave Hill has now revealed what the terrifying sigil means, and it probably won't help you get to bed, to be honest.
Speaking to the New York Post in a wide-ranging interview, Hill explained: "As we saw with Bran and the Three-Eyed Raven, the spiral pattern was sacred to the Children of the Forest, who created the Night King by sacrificing a captured man in a spiral 'henge of stones'.
"The Night King then adopted the symbol as a sort of blasphemy, like Satan with the upside-down cross."
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In equally horrifying news, Isaac Hempstead Wright, who plays Bran Stark on the HBO show, recently revealed that his parents had to teach him about incest after filming the scene in season one where he catches Cersei and Jaime having sex.
Game of Thrones season 8 airs on HBO in the US and Sky Atlantic and NOW TVin the UK. Tune in to Digital Spy's Game of Thrones livestreams on Monday evenings, straight after each episode, on Instagram and Facebook.
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