In Hesiod’s Greek myth of Pandora, evils escaped when she lifted the jar’s lid.
In Works and Days, Hesiod presents Pandora as part of Zeus’s punishment of humanity after Prometheus gave humans fire. Zeus arranged for Pandora to receive a sealed container, and opening it released destructive conditions that had previously been kept away from human life. Hesiod lists suffering in forms including disease, exhausting labor, and other troubles.
The myth does not primarily describe monsters flying out of the vessel. Its contents are personified or generalized evils that explain why human existence includes pain and hardship. This makes the story a mythological explanation of the human condition rather than an adventure about a magical treasure chest.
The expression “open Pandora’s box” now means to trigger many unforeseen problems. In the ancient story, however, the release is specifically linked to the arrival of evils among mortals. Hope remains associated with the container, but its exact status has been debated since antiquity.