The Quantum Weather Butterfly ( Papilio Tempestae ) is an undistinguished yellow color, its outstanding feature is its ability to create weather. This presumably began as a survival trait, since even an extremely hungry bird would find itself inconvenienced by a nasty localized tornado ( usually about 6 inches across ). From there it possibly became a secondary sexual characteristic, like the plumage of birds. Look at *me*, the male says, flapping his wings lazily in the canopy of the rain forest. I may be an undistinguished yellow color but in a fortnight's time, a thousand miles away, Freak Gales Cause Road Chaos. This is the butterfly of the storm

Terry Pratchett