Pan ‧ do ‧ ra’s box /pænˌdɔːrəz ˈbɒks $ -ˈbɑːks/ BrE AmE noun
[ Date: 1500-1600 ; Origin: Pandora woman in an ancient Greek story who opened a box and let all evils out into the world ]
open a Pandora’s box to do or start something that will cause a lot of other problems:
The report could open up a Pandora’s box of claims from similar cases.