A fictional persona which one "wears" like a suit. Coined by writer Grant Morrison[1].
A fiction suit can be used to interact with fictional/historical characters. For example, in his comic book, The Invisibles[2], Grant Morrison used the character King Mob[3] as a fiction suit. He soon discovered that whatever happened to his fiction suit would happen to the "real" him. One can easily see how this can be extremely advantageous - and perhaps dangerous.
A fiction suit can also be used in the "real" world. When worn in this fashion, a fiction suit becomes something similar to Robert Anton Wilson's[4] idea of a "reality tunnel". One constructs the fiction suit, with all of the persona's passions, prejudices, quirks and perspectives and then "puts it on", essentially becoming it. This can be used to test a model of reality, experiment with various modes of social interaction or as a method of testing and refining a "beta version" of an aspect of the gestalt personality/mind/body that is being considered for an upgrade.