What will happen with Bitcon when stock market crashes?
The stock market crash is imminent. It's not about "if", it's about "when".
I expect also precious metals and cryptocurrencies to drop in value and their bottom to happen before the bottom of the stock prices.
It's known from the behavioral economics that low liquid assets react more fast to the panic selling (panic buying).
Here you can see how the bottom of the gold price occurred before the bottom of the stock prices: