to watch out for someone, or something
"Oh shoot, the cops, 2319"
"2319, here come Rebecca"
a company or factory code in the Monsters Inc. world. When an employee is contaminated with a foreign object of a human child, a 2319 goes into effect and alerts the Child Detection Agency (CDA). The CDA removes and destroys the foreign object, shaves and cleans the employee from any contamination and puts a cone around his head to protect himself from biting.
The number 2319 is also seen on car's license plate. It is also a reference to the Old Testament Exodus 23:19.
2319! We have a 2319!