It's down more than 50% after hours
It was a rough day for bets against volatility. One of the most-popular ways to do this is via the ETF XIV along with SVXY.
The XIV uses VIX futures and moves inversely to the VIX. In plain English: It rises as volatility falls. When volatility jumps, like it did today, then it gets beaten up. It's not based on the front-month VIX but a range of futures 6-9 months out, so it's not as wild as the VIX itself.
Needless to say, it was a rough day for anyone long XIV (and it's a crowded trade). It fell to 99 from 115 in regular trading.
This is where it gets interesting. After hours, it's fallen as low as 32. Yes, 32.
No one really knows what's going on and even Cramer is hitting the panic button and having a meltdown on twitter.