Which modern phrase comes from Pandora’s myth and describes an action causing many unexpected problems?

The phrase “opening Pandora’s box” describes an action that causes many unexpected problems.

Its meaning comes from the myth in which Pandora opens a container and releases suffering into the world. In modern English, the phrase is usually metaphorical: a decision, investigation, or invention may reveal consequences that are difficult to control or reverse. The expression is used in journalism, politics, science, and everyday conversation.

The idiom is based on the later “box” version of the story, while Hesiod’s earliest surviving account describes a jar. That translation history does not change the phrase’s meaning. “Opening Pandora’s box” is also distinct from “opening a can of worms,” another expression for creating complications; the Pandora phrase specifically invokes the Greek myth.