“Almost all non-literate mythology has a trickster-hero of some kind. […] And there’s a very special property in the trickster: he always breaks in, just as the unconscious does, to trip up the rational situation. He’s both a fool and someone who’s beyond the system. And the trickster represents all those possibilities of life that your mind hasn’t decided it wants to deal with. The mind structures a lifestyle, and the fool or trickster represents another whole range of possibilities. He doesn’t respect the values that you’ve set up for yourself, and smashes them. […] The fool is the breakthrough of the absolute into the field of controlled social orders.” — Joseph Campbell
The trickster is chaos. He (or she or both) is entropy. Decaying, changing your plan and making you continue the struggle against complacency. In complacency is death and the trickster gives life.
Thank you to Elucipher for posting the Campbell quote.