Although audiences have come to know Game of Thrones for its battleground warfare, poison has become a powerful weapon throughout the seasons. Here are three of the most devastating uses of poison thus far:
Joffrey's Death via the Strangler
King Joffrey Baratheon dies at his wedding feast thanks to Olenna Tyrell's use of the strangler. This poison comes in the form of amethyst-coloured crystals and works immediately after ingestion. The victim's throat swells shut and blood to leaks from the pores. Joffrey's death by strangler sends a schism through the Lannister family when Ceresi assumes her brother Tyrion is at fault.
Oberyn's Poisoned Spear
During the Trial for Combat to determine Tyrion's fate, Oberyn Martell uses a poisonous spear against Gregor Clegane a.k.a The Mountain. Oberyn's aerial acrobatics allow him to wound Gregor severely enough to strike a final deathblow. Unfortunately, Oberyn becomes so carried away with exposing Gregor's involvement in his sister's murder that the Mountain regains the upperhand and crushes Oberyn's head—moments before succumbing to the effects of the poisoned spear.
The Long Farewell
In the fifth season, as Jaime and his niece/daughter Myrcella leave Dorne for King's Landing, Ellaria Sand poisons Myrcella with the Long Farewell, using an innocent kiss on the lips. Even though both are poisoned, Ellaria survives when her daughter Tyene produces an antidote. Myrcella is not so lucky. As her nose begins to bleed, we know the poison has become fatal.
In an interesting twist, Cersei Lannister uses this poison (and antidote) in the seventh season to unleash her wrath on the Sands for murdering her daughter. This time Tyene is the victim of Ceresi's poisonous kiss and Ellaria must watch her daughter die when the Queen locks the pair in a dungeon together.