How is “a can of worms” used?

In Deathtrap (1982), one line is: “You will be opening up a very messy can of worms.”

Which movie is “a can of worms” from?

The clip at the top of this page is from Deathtrap (1982).

if you open up a can of worms, you start doing sth that will cause a lot of problems and be very difficult

informal · Heard in 5 moviesPlay Idioms

Oxford100% of films
if you open up a can of worms, you start doing sth that will cause a lot of problems and be very difficult
I was attempting to give them Eltenton without opening a can of worms.

Definitions from the Oxford Advanced Learner's Dictionary, 9th edition

You will be opening up a very messy can of worms.

Said in 6 films · #1