Flash mob (open water)
noun - A flash mob (open water) or a splash mob is a group of swimmers who assemble suddenly in a public beach, or open body of water, enter the water to swim or perform unusual and seemingly pointless actions for a brief time, then quickly disperse, often for the purposes of entertainment or expression. As on land, flash mobs in open bodies of water are organized via telecommunications, social media, or viral emails.
Flash mobs, first coined in 2003 by Harper's Magazine's senior editor Bill Wasik, is not applied to events and performances organized for the purposes of politics, protests, commercial advertisement, or publicity stunts that involve public relation firms or paid professionals. In these cases of a planned purpose for the social activity in question, the term smart mobs is often applied instead.
 Flash mobs vs. Smart mobs vs. Splash mobs
A smart mob is a group of individuals that behaves intelligently or efficiently because of its exponentially increasing network links, enabling people to connect to information and others, allowing a form of social coordination. The concept was introduced by Howard Rheingold in his book Smart Mobs: The Next Social Revolution. According to Rheingold, smart mobs are an indication of the evolving communication technologies that will empower the people. In 2002, the "smart mob" concept was highlighted in the New York Times "Year in Ideas." There is a tendency to keep the dynamics of smart mobbing 'covert', and not to discuss such incidents on the internet.