let the genie out of the bottle

To create, unleash, or do something that creates a huge impact and cannot be stopped or reversed. Now that the report let the genie out of the bottle regarding the government's surveillance policies, public trust has been permanently damaged. I doubt the people who first conceived of the Internet could have known how they'd be letting the genie out of the bottle.

let the genie out of (or put the genie back in) the bottle

let loose (or bring back under control) an unpredictable force, course of events, etc.

A genie or jinnee in Arabian stories is a spirit that can adopt various forms and take a mischievous or benign hand in human affairs. The genie generally inhabits a lamp (compare with Aladdin's lamp at aladdin) or bottle from which someone can release it by the appropriate words or actions. The Arabic word appears in English in various transliterations; genie derives from French génie (from Latin genius meaning ‘a tutelary spirit’), used by the French translators of The Arabian Nights because it was similar in form and sense to the Arabic word.

2002 Chicago Tribune Keeping the nuclear genie in the bottle has not been easy. India and Pakistan have both developed nuclear weapons in recent years.

let the ˌgenie out of the ˈbottle

do something that causes a big and permanent change in people’s lives, especially one which might make a situation worse: Once you make carrying guns legal, you let the genie out of the bottle.

In Arabian stories, a genie is a spirit with magical powers, especially one that lives in a bottle or lamp.