The dramatic video footage often appears on TV news and social media: A large group of people storm into a store, smashing display cases and snatching loose merchandise before escaping in minutes ...

Right now, a very unique social media phenomenon that began in Germany is spreading in Europe and starting to appear in the United States, as well.

A term originally associated with fun has turned more menacing.In popular culture, flash mob has also come to be associated with a large outpouring of violence, such as those that have plagued the ...