A caterfly effect occurs from the action of a cat affecting the surroundings and actions of humans which in turn creates a exponential reaction.
when a cat
walks out into the street and a car swerves to avoid it and collides with a wall, later the female passenger dies leaving behind her husband.
He happens to be a major stock broker who suffers a nervous breakdown at work creating a crash in the stock market which affects a rare earth mine located in Africa by bankrupting the owning Chinese corporation eventually causing the economy of the African country to collapse.
The current refugee crisis for example can be traced back to a cat yawning creating a Caterfly effect.