The big boys got caught with their shorts down.
Short sellers borrow stock in order to sell it without actually owning it. When you spot a stock with more share sold short than actually exists all you need to do is buy calls and then buy the stock and tell your broker to not lend your stock. When the short sellers try to borrow more and no one is lending, they have to buy or go to prison The price of your calls goes up and the people who sold you your calls try to buy too, so the price goes up. It is a wonderful spiral for you and a horrible event for the short sellers and the call sellers who are usually the big boys.