Pan·do·ra's box 
/pænˈdorəz-/ noun
/pænˈdorəz-/ noun [singular] : a source of many troubles : something that will lead to many problems
▪ Her parents are understandably afraid of opening a Pandora's box [=causing many worries and problems] if they buy her a car.
▪ Her parents are understandably afraid of opening a Pandora's box [=causing many worries and problems] if they buy her a car.
