/ pænˌdɔːrəz ˈbɒks; NAmE ˈbɑːks/ noun
[ sing. , U ] a process that, if started, will cause many problems that cannot be solved :
This court case could open a Pandora's box of similar claims.
ORIGIN: From the Greek myth in which Pandora was created by the god Zeus and sent to the earth with a box containing many evils. When she opened the box, the evils came out and infected the earth.