The death of Dany's brother, Viserys, in season 1 has been found to be the show's fastest way to die. Khal Drogo poured the molten gold over his head, and he would have died from a boiling brain. A researcher found that molten gold has a temperature of around 1947 degrees F, and the brain - being mostly water (73 percent), would boil extremely quickly. Death would occur in about 3.5 seconds, and he would probably never even feel the heat. This would be the most merciful death on the show.