For those curious, here is a stupid (and basic) explanation for shorting stocks:
You own a share of stock worth $100. I don't think it is worth $100, so I "borrow" it from you (for fee) and sell it. I now have $100 and you have an IOU for 1 share of stock at its current value. 1/

If in 2 months, the price of that stock drops by 50%, I buy 1 share for $50 and give it back to you. You now have your original stock (+ fee) and I have the difference in price between what I sold it for, and what I bought it back for ($50). 2/

When you short a stock, you can only make 100% of the value of the stock and that would only be if it goes to zero. So what happens when the price goes up instead of falls? Now you have to pay more than the original value and you can get majorly screwed 3/

For example, if that $100 stock that you started with triples to $300 and the original owner wants it back, then you must pay $300 to repurchase that it and deliver it to the original owner, thereby ending up $200 down. 4/

So what happened with GameStop (and the others)? Internet people noticed that a lot of hedge funds had shorted these companies and therefore "owed" stock in them. By driving up the price, that forced the funds to cover their shorts and repurchase the shares 5/

This drove the price up even more and causes a "short squeeze" where people on the wrong side of the bet rush to close their position before losing too much and the pattern continues. 6/

Where this ends, who knows? Somebody out there is holding overvalued shares of struggling companies and will be caught when there's no longer any buyers for them. Heck, right now might be a good time to short GameStop... if you're brave.