What happens whan something that "cannot happen" happens. If you don't knwo what a statictical outlier is, then the DJIA selloff on monday february fith 2018 may be difficutlt to undrstand. Simpy explained it was a bet on being short the CBOE VIX or long the inverse of the VIX. When volatility in the market is low, you earn money, but when volatility increases, the inverse 1/VIX falls. In other words, it was a bet on low volatility.