The English phrase for a source of unforeseen troubles that comes from the myth is “Pandora’s box.” In everyday usage, opening Pandora’s box means starting a process that releases many unexpected problems.
The expression is based on the later popular form of the story, in which Pandora opens a box and releases evils into the world. Hesiod’s original Greek account describes a pithos, or large storage jar, rather than a small box. The box wording became established through translation history and later European retellings.
The phrase is usually used metaphorically, not as a claim that the myth’s object was literally a hinged box. It is also distinct from other myth-based idioms: an Achilles’ heel is a vulnerability, a Gordian knot is a difficult problem, and the Midas touch refers to an ability that turns things into wealth or success. “Pandora’s box” specifically emphasizes consequences released by an action.