"Pandora's Box" metaphors

The majority of definitions give the same meaning - "Pandora's box" is a synonym for "a source of extensive but unforeseen troubles or problems."

Are there any other metaphors with the same meaning?

Solution 1:

to open (up) a can of worms may suggest the same situation:

to create a situation that will cause trouble or be unpleasant The investigation into how these expensive trips were paid for certainly opened a can of worms.

• Usage notes: sometimes used without open up: I don't think her plan will work - it seems like kind of a can of worms to me.

Source:http://idioms.thefreedictionary.com/open+a+can+of+worms

Solution 2:

A similar phrase is let the genie out of the bottle, meaning

to allow something bad or unwanted to happen that cannot then be stopped [Cambridge Dictionaries Online]

Solution 3:

To open a hornets nest or stir up a hornets nest comes close to the sense of Pandora's box. I suppose one difference is that in the original myth, the consequenses of opening the box were not forseen, whereas if you describe someone as opening a hornets nest you tend to imply foolishness or short-sightedness or recklessness. On the other hand, I'm not sure that common usage of Pandora's box preserves the sense of unleashing harm unknowingly.