VIX is based off of the S&P 500 options premiums. There’s not an options market on crypto baskets that I know of (yet).

VIX is a variance swap, so a "CryptoVIX" would move in line with the expected short-term realized volatility of a basket of cryptocurrencies, not their price.

It'd certainly be possible to price such an index (replicating strategy of portfolio of strips of calls/puts of various cryptocurrencies) but it'd be impossible to hedge because transactions costs are too high. You could hedge with crypto-options, but AFAIK they don't exist yet.

Short Overstock. It moves very closely in align with crypto.

Bitcoin down almost 70% since high