4. Oberyn Martell Vs. Ser Gregor Clegane
Fourth season, third casting for Ser Gregor Clegane. This time it is the turn of Hafþór Júlíus Björnsson to take up the role and he'll have the opportunity to play the character in probably his most defining and ultimately influential moment. You see, it is this trial by combat that begins a motion to bring Daenerys Targaryen to Westeros. In the books, Clegane raped and killed Martell's older sister Elia she was married to Prince Rhaegar Targaryen, and killed her infant child Aegon VI Targaryen. Oberyn swore revenge and when Tyrion Lannister requests trial by combat for a murder he didn't commit and after Cersei has Gregor Clegane act as her champion, Oberyn sees this as an opportunity to kill the mountain. We already saw a trial by combat back in season one, where Tyrion was victorious. Think of that as a four. Now imagine it turned up to a ten. Oberyn is known as the Red Viper, a master of poison and Clegane is a mountain of a man. In the end they both die. Oberyn uses poison and mortally wounds Clegane, who is forced to admit he raped and killed Elia before he tricks Oberyn and caves his skull in making Tyrion technically lose the trial. Gregor Clegane should then spend the rest of the season dying a miserable death much to the joy of Sandor Clegane fans. However, that isn't the end of Gregor as it is rumoured that Ser Robert Strong is actually his reanimated corpse although that might be difficult as he gets beheaded after his death with the skull presented to Oberyn's daughters.