What modern expression means unleashing unexpected trouble by investigating Pandora’s Box?

The modern expression is “opening Pandora’s box.” It means starting an action or investigation that releases many unexpected problems and becomes difficult to control.

The idiom comes from the Greek myth in which Pandora opens a sealed container and allows troubles to escape into the human world. The phrase is commonly used in journalism, politics, law, science, and everyday conversation when a seemingly small decision produces far-reaching consequences.

The expression is related to, but not identical with, the ancient story. Hesiod described a pithos, or large jar, and did not use the modern English phrase. The “box” image became established through later translation and retelling. “Opening Pandora’s box” is now recognizable even among people who have never read Hesiod’s poems.