A mushroom cloud is a distinctive pyrocumulus mushroom-shaped cloud of debris/smoke and usually condensed water vapor resulting from a large explosion. The effect is most commonly associated with a nuclear explosion (and sometimes referred to in this context as a thunderball), but any sufficiently energetic detonation or deflagration will produce the same sort of effect. They can be caused by powerful conventional weapons, like vacuum bombs, including the ATBIP and GBU-43/B Massive Ordnance Air Blast. Some volcanic eruptions and impact events can produce natural mushroom clouds.