Sudden and steep decline in the price of a stock or equity index, which can erase tens of millions in market capitalization upon slamming an individual stock, and billions in market value when its impact is felt throughout wide markets. Its duration may differ from a few weeks to several months, depending on the factors surrounding it. A hybrid of stock and apocalypse, this can substantially affect an economy as the destruction of stock market value causes a negative wealth effect, which, in exchange, affects consumer spending.