200k redditors pump the price.
Simple terms,
Hedge fund short the stock hoping when it goes down they will profit.
Example price now 50rm, if drop to 20rm the hedge fund pocket 30rm difference.
But when 200k ppl buy 1000rm each, the price from 50rm go to 90rm. So instead of pocketing the loss they need to pump more money in to cover the bet.

Hedge fund didn't buy the stock but make a bet saying will go down.
So when go up they are negative losses.
Now when everyone pump to 200rm, the hedge fund need to cover 150rm loss in each stock.
So if hedge fund bet 100k unit at 50rm to go down, now since it goes up, that 100k units is at -150rm per unit.

So their losses at 100k X 150rm which is 15mil.

But from what I read, it was from 20 over USD to 150 over USD..

So imagine if you buy 10 mil unit at 20 usd, if price goes down to 10 you will win 100mil USD. Now it's 10mil units X 130usd so your losses will be 1.3billion