A granfalloon, in the fictional religion of Bokononism (created by Kurt Vonnegut in his 1963 novel Cat's Cradle), is defined as a "false karass." That is, it is a group of people who outwardly choose or claim to have a shared identity or purpose, but whose mutual association is actually meaningless.
The most commonly purported granfalloons are associations and societies based on a shared but ultimately fabricated premise. As examples, Vonnegut cites: "the Communist Party, the Daughters of the American Revolution, the General Electric Company —and any nation, anytime, anywhere." A more general and oft-cited quote defines a granfalloon as "a proud and meaningless association of human beings." Another granfalloon example illustrated in the book were Hoosiers, of which the narrator (and Vonnegut himself) was a member.
If you wish to examine a granfalloon, just remove the skin of a toy balloon. — Bokonon
"My God," she said, "are you a Hoosier?"
I admitted I was.
"I'm a Hoosier, too," she crowed. "Nobody has to be ashamed of being a Hoosier."
"I'm not," I said. "I never knew anybody who was." – Kurt Vonnegut, Cat's Cradle
They had found a can of white paint, and on the front doors of the cab Frank had painted white stars, and on the roof he had painted the letters of a granfalloon: U.S.A. – Kurt Vonnegut, Cat's Cradle
Granfalloon Technique 
The granfalloon technique is a method of persuasion in which individuals are encouraged to identify with a particular granfalloon or social group. The pressure to identify with a group is meant as a method of securing the individual's loyalty and commitment through adoption of the group's symbols, rituals, and beliefs. In social psychology the concept stems from research by the British social psychologist Henri Tajfel, whose findings have come to be known as the minimal group paradigm. In his research Tajfel found that strangers would form groups on the basis of completely inconsequential criteria. In one study Tajfel subjects were asked to watch a coin toss. They were then designated to a particular group based on whether the coin landed on heads or tails. The subjects placed in groups based on such meaningless associations between them have consistently been found to "act as if those sharing the meaningless labels were kin or close friends."
Researchers since Tajfel have made strides into unraveling the mystery behind this phenomenon. Today it is broken down into two basic psychological processes, one cognitive and one motivational. First, knowing that one is a part of this group is used to make sense of the world. When one associates with a particular group, those in the group focus on the similarities between the members. This is different from people not in the group. For "outsiders" differences are focused upon and often exaggerated. A problem with the granfalloon is that it often leads to in-group, out-group bias. Second, social groups provide a source of self-esteem and pride, a form of reverse Groucho Marxism as in his famous remark "I don't care to belong to any club that would have me as a member."
Granfalloon in popular culture 
- In the 1997 video game Castlevania: Symphony of the Night, a boss was termed Granfalloon. It took the form of a huge ball of naked human corpses held together from within by a monstrous tentacled parasite. The monster's original Japanese name was Legion, as it is now called in the later translations.
- On the Carole King album Tapestry, James Taylor is credited with playing the Acoustic Guitar and the Granfalloon
- Granfalloon (fanzine) is the name of a Hugo Award-nominated science fiction fanzine.
- The Granfaloon is also a bar in Kansas City. 
References and footnotes 
- Book Review of Age of Propaganda by Anthony Pratkanis and Elliot Aronson, Alison Carpenter
- Billig, Michael; Tajfel, Henri (1973). "Social categorization and similarity in intergroup behaviour". European Journal of Social Psychology 3 (1): 27–52. doi:10.1002/ejsp.2420030103.
- Pratkanis, Anthony R.; Aronson, Elliot (1992). Age of Propaganda (Rev. ed.). New York: Owl Book. pp. 214–223.
- Devilly, Grant J. (2005). "Power Therapies and possible threats to the science of psychology and psychiatry". Australian and New Zealand Journal of Psychiatry 39 (6): 437–45. doi:10.1111/j.1440-1614.2005.01601.x. PMID 15943644.
- "Granfaloons Website".