In Game of Thrones Season 4, Episode 8, “The Mountain and the Viper”, we witnessed the gruesome death of Oberyn Martell (Pedro Pascal) at the hands of the Mountain, Gregor Clegane (Thor Bjornsson). However, the Mountain collapses and appears pretty lifeless at the end of their fight, so is he dead as well?

Warning! This article contains spoilers from the A Song of Ice and Fire book series, click away now if you don’t want to know!

The Mountain survives the fight with Oberyn... for a time, at least. In the books, it is later revealed that Oberyn used a poison-tipped spear during the fight (hey, the don’t call him the Red Viper for nothing), and the poison he used was a particularly nasty one. It causes the Mountain a long, drawn-out, agonizing death. Grand Maester Pycelle is unable to ease Gregor’s pain, so Cersei gives the task to Qyburn. The Mountain eventually dies while he is in Qyburn’s care, and his massive skull is sent to Dorne to appease for Oberyn’s death (aww, they shouldn’t have).

However, that’s not the end of the Mountain’s story. Later, a new knight shows up in town, seemingly discovered by Qyburn. The knight’s name is Ser Robert Strong, and he is just as big as the Mountain. Curiously, he doesn’t eat or speak, and no one has ever seen him remove his helmet. Many fans believe that Qyburn, who’s King’s Landing’s version of a mad scientist, has somehow reanimated the Mountain’s corpse, sans head, and is passing him off as Robert Strong, though we may have to wait for The Winds of Winter’s 2034 release for confirmation.

Catch the next episode of Game of Thrones Season 4 on June 8, 2014 at 9 p.m. ET on HBO.