dedicated to Kinga
In case you don't know, worms are those pinkish, thin snakelike creatures that live in wet soil and birds like to eat so much.
(The early bird catches the worm)
However, back to the can of worms, that's not so good.
If you open up a can of worms you investigate something or say something that has a lot of negative consequences; one problem leads to another.
'You've opened up a real can of worms now!'
Just to prove that I haven't made this one up, here's the start of a Disney film by the same name.
Don't forget the popcorn- or worms if you're a bird!