Prune602's question "so... what do they do next?" has an obvious answer.
They create rubles out of thin air.
Deficit spending. Devaluing the currency. Probably flooding the financial industry with the liquidity, too.
The problem: where does it stop, who gets bailed out, and where's the revenue & demand to support such a deficit?
It's odd for an American to lecture others on deficits, but US' spending is predicated upon a HUGE economy with the world's most used & pegged currency.
🇷🇺s isn't.