When she throws it among friends, their friendship come to a rapid end. When she throws it among enemies, war breaks out, for the golden apple of Eris is the Apple of Discord. She did this once during the wedding of Peleus and Thetis, and this act brought about the Trojan War.
Eris was angered by the fact that she was not invited to the wedding. But seriously, why would anyone want her to be at their wedding when she was nothing but the ultimate drama queen and troublemaker. She tossed her golden apple onto the wedding table and announced it to be for the fairest. The goddesses Hera, Athena and Aphrodite each wanted to claim it and each reached for the apple. Zeus proclaimed that Paris, prince of Troy and thought to be the most beautiful man alive, would act as the judge.
Each of the three goddesses immediately attempted to bribe Paris to choose her. Hera offered political power. Athena promised skill in battle. Aphrodite tempted him with the most beautiful woman in the world: Helen, wife of Menelaus of Sparta. While Greek culture placed a greater emphasis on prowess and power, Paris chose to award the apple to Aphrodite, thereby dooming his city, which was destroyed in the war that ensued.
The classic fairy tale Sleeping Beauty is partly inspired by Eris's role in the wedding of Peleus and Thetis.