a can of worms

a can of worms

  (informal)
a situation which causes a lot of trouble for you when you start to deal with it Quite what we do with all the waste generated by this industry is another can of worms. Once you start making concessions to individual members of staff, you really open up a can of worms. (= cause a lot of trouble for yourself)
See also: can, of, Worms
References in periodicals archive ?
When I was little I always went to my grandmother's house to rummage through her compost pile and bring a can of worms home for my room, who accepted them gratefully and later dumped them in her flower garden.
A PET lover opened a can of worms when a tin of cat food exploded, showering her with maggots.