The world of Game Of Thrones changed forever when Daenerys Targaryen walked into the dragon egg-adorned funeral pyre of Khal Drogo, and walked back out not only alive, but with three baby dragons as well. While the ramifications of that have played out throughout the series, and will continue to have more importance as it approaches its endgame, there was another takeaway from it: Daenerys, and thus Targaryens, are fireproof. The theory was certainly understandable, given Dany had literally just survived the flames, and their links to dragons and fire in general (the Targ words are "Fire and blood"). What made this theory more important was that it was seen as a way of potentially debunking R+L=J, since Jon Snow had his hand burnt and clearly wasn't immune to fire, and as such can't be a Targaryen. However, it discounts the fact that Viserys was killed by molten gold, and there have been other examples of Targs being killed in fires throughout Westeros history, including King Aegon V Targaryen, younger brother of Maester Aemon. Martin himself has confirmed that Targaryens are not fireproof, including Dany, and that the funeral pyre was "unique, magical, wondrous, a miracle."