It's a battle with the people with an financial incentive/bet that the stock will go down. These people have essentially borrowed shares and sold them on the m

It's a battle with the people with an financial incentive/bet that the stock will go down. These people have essentially borrowed shares and sold them on the market (short sale), and are waiting at some time in the future to buy them back. The idea is they will buy the stock back at a much lower price than they originally sold them for. The people holding the IOUs for gamestop stock are paid regular interest payments. These payments are relative to the price of gamestop. The higher the stock price goes, the higher the interest payments are. When the stock skyrockets like this, a positive feedback loop is generated (called a short-squeeze), people want to buy back shares to stop their interest payments on the IOUs. And if there aren't enough shares available, the price spikes. Eventually, the market cools off and the price plummets back to earth.