In early 2021, ordinary retail investors mounted an assault against Wall Street hedge funds. Mobilizing on Reddit and relying on user-friendly trading apps like Robinhood, amateur investors sparked a short squeeze in the market for video game retailer GameStop's GME stock. Working together, they drove the share price sky-high, crushing short sellers before company fundamentals returned the stock price down to earth. The siege left financiers reeling. Ultimately, the saga spawned Congressional hearings and, more recently, regulatory action from the Securities and Exchange Commission (SEC).