Spoiler alert: This post contains spoilers for season one of Game of Thrones. So if you haven't seen any of the show, and plan to, you should stop reading now.
HBO's recent announcement that the next season of Game of Thrones won't premiere until the summer of 2017 (and will run a mere seven episodes) means fans of the hit series have plenty of extra time to speculate about what might happen next. While the sixth season's "Hodor is a horse" theory had no legs, arguments rage on about the three-headed dragon theory, and R+L=J has already been confirmed by HBO via a blog infographic. But there are still several questions looming as we head into the series' final two seasons, one of which is whether or not Daenerys' late husband, Khal Drogo, might return.
In case you forgot, here's a quick recap: Khal Drogo was wounded in battle and then "saved" by the captured witch Mirri Maz Duur with blood magic, but the procedure left him in a catatonic state and led to his son with Daenerys, Rhaego, being stillborn. Ever the dutiful wife, Dany put Khal out of his misery by smothering him with a pillow, then burned his body—along with Mirri Maz Duur—before walking into the flames herself, emerging naked and unburnt with newly hatched dragons and a whole new story arc.
In both the book and the series, Dany asks Mirri when her husband will return to his pre-catatonic state. Mirri replies, "When the sun rises in the west and sets in the east, when the sea goes dry and mountains blow in the wind like leaves, when your womb quickens again and you bear a living child. Then he will return, and not before." Taken literally, the prophecy sounds sort of like "never," but redditor MrMaschocist thinks that it is one big metaphor, writing:
"The Frog Prince is Dornish (sigil is a sun transfixed by a spear) and he makes his identity first known (rises) in Westeros, before travellng east to Essos to meet Dany and free Viscereon and Rhaegal (who kill him ... setting the sun's son) or—the sun rises in the west and sets in the east ... Dany's final chapter suggests that the Great Grass Sea has succumbed to drought and died off, at least in the area she can see OR—the sea has gone dry ... After Rhaegal and Viscereon kill the Frog Prince they escape the pyramid by bursting free of the great structure, destroying it. The pyramids are referenced to nearly be as high as the Wall, so they are certainly 'mountains' OR—mountains blew in the wind like leaves ... And Dany's final chapter ends with her period returning. She hasn't remembered her moonflow for some time, perhaps since she had the miscarriage. OR—her womb quickens again ...
The fan theory continues by saying that Dany and Jon Snow will become a couple, they'll "catch the love disease and make a baby," and Khal Drogo will be resurrected as Azor Ahai who, according to Game of Thrones Wikia, is a warrior prophesized in ancient books who is armed with a powerful blade pulled from the fire.
Because the makers of the show have diverged from the narrative of the book, some of the references made by MrMaschocist were never shown on screen (including the character of the Frog Prince). If Khal Drogo were to return in the series, the events leading up to that point—and the explanation—would have to change. But that doesn't rule the theory out as a possibility for George R.R. Martin's books. Or, maybe Mirri Maz Duur just liked using riddles to insult people.