In a LARP, the tendency for neutral or good characters to coalesce into a mob on the last day of a game and go hunting for bad guys, especially those engaged in destroy the world plots. Clever evil characters will insinuate someone into the mob to provide misdirection (or direction towards enemies.

Good guy mobs tend to also form for protection, especially after a common room massacre; innocent bystanders want to be in a fairly safe place from random violence.