opening up a can of worms??

[mully]

Where does the phrase -Opening up a can of worms come from and what does it mean?

[Quizmonster]

The earliest recorded use of the phrase "open a can of worms" was in 'The Times' in the early 1960s, though it probably existed in speech prior to that time. It means that you are exposing 'a mass of troubles', all entangled with each other, in the same way as you would find worms wriggling together in a can. Always best to leave the can closed!
Much the same meaning is found in the saying "open a box of frogs".  If you imagine actually opening either of these things, what you'd see inside is a mass of entwined, writhing, damp creatures which you wouldn't want to touch and which would be almost impossible to disentangle and sort out. The same applies to such 'problems' in real life...if you can avoid them, do!

[Mr.Ix]

I always equated it to the magicians / Clowns prop of spring loaded tubes that used to explode out when he opened them. Easy to open, not easy to put them back in

[jocook17]

I agree with Mr.Ix as those magician things are also supposed to be shocking - although I thought they were snakes??