What looks, at the start of 2021, like a struggling retailer of video games during a pandemic—GameStop—with a stock price hovering around $17 a share, and a rash of short sellers hoping for a bankruptcy filing, is suddenly transformed three weeks later into a “stonk” and a cable-TV business-news sensation: Seemingly overnight, GameStop’s share price rockets up to around $350 per share, with a market valuation around $20 billion. Forget the fundamentals. They make no sense.