Sorry if i mess up some details but I will try.

Greedy hedge funds were betting GameStop stock would tank and possible go out of business. They got so greedy that they had more bets against the company than stocks existed. So small investors saw this and decided to grab on to opportunity.

If they and many other small fish would start buying GameStop(GME) stock and betting on the stock going up, then they could create a unique thing called a "Short Squeeze". Meaning the stock price would rise forcing the hedge funds to buy GME stock on the open market to cover their bet. Confusing I know but stick with me.

So now a chain reaction of buying frenzy happen on GME stock. Retail(small) investors are buying the stock and so must the hedge funds. But there is not enough stock to go around so the price EXPLODED. GME stock became as rare as diamonds it seems. but the hedge fund MUST get the stock so they are forced to pay insane prices, the most GME people bought and held the higher the price went. The small fish had the hedge fund "over the barrel" as they say. Billions of dollars were lost by rich hedge funds.

These internet pranksters have invested small amounts and made small fortunes already. But much like the Joker they claim they aren't in it for the money but to send a message to Wall Street. They claim they will take GME to $1000 from it's normal price of just $10. It's around the $350 marks as of this writing.

In addition the peasants have targeted other heavily shorted stocks to make hedge funds bleed. Will it work? Who knows.