actually i have no idea for facing these situations but if this is come true i think i would still for bitcoin and would buy it as much as I can and i think i would save my bitcoin into cold storage till hoping that someday the prices will rise up again
If it happens, which is pretty much impossible. the we can't do anything really. we can't even sell our bitcoin for low price which we bought for 200$ to 400$ each.
there will be only option for us to hold our bitcoin for more time and wait for again it's price increase.
but it is just a thought. there is no reality on it . how an altcoin can dump bitcoin?