I let the worm out of the bag

The speaker was trying to say “I opened a can of worms” but instead uttered this mashup of  “opening up a can of worms” (a situation that once started will have a negative outcome) and “let the cat out of the bag” (to reveal a secret by accident). Both describe opening up something. “Bag worms” also might have been on the speaker’s mind. Regardless, this is a nice incongruent conflation (blend of two idioms with different meanings). A big thanks to Erik Ivison for unintentionally saying this one and sending it in!