A term started in Battlefield 3 that has been called "the only definitive way to say a lot of kids". A group of kids in a video game that pose a threat to your team. Can be used in real life but has yet to be done.
You'd probably want to say it around a group of shady minority youths.
"Kids coming from the crane, there's like one tw- MASS KIDS! MASS KIDS AT CRANE"