The Child Detection Agency announces code 2319 for a human object in Monsters, Inc.
The code is heard when a monster returns to the scare floor with a human child’s sock attached to his back. CDA workers immediately respond, remove the contaminated object, and decontaminate the monster. The alarm becomes one of the film’s most recognizable comic moments.
Code 2319 is not the name of a character, machine, or location. It is an emergency contamination code used by the Child Detection Agency, the organization that monitors possible contact between monsters and human children. The film uses the code to establish how seriously monster society treats anything from the human world.
The sequence also sets up a recurring joke: characters repeat “2319” with dramatic urgency, while the audience can see that the supposed danger is only a small sock. Later scenes involving Boo make the code’s exaggerated fear more relevant to the wider story.