Pandora's Box is a term used quite often to describe a situation which can lead to unexpected consequences. The phrase is derived from an ancient Greek myth where Pandora, the first woman, was given a box as a gift. Despite being warned not to open it, Pandora gave in to curiosity and unleashed all the evils of the world, leaving only hope trapped inside. Some synonyms for Pandora's Box include "can of worms", "a hornet's nest", "a slippery slope", "a minefield", and "a ticking time bomb". All these phrases indicate complications or challenges that can arise when a decision is made, much like Pandora's Box.
