Keith Gill, who goes by the handle “Roaring Kitty,” earlier brought meme stock traders back to GameStop through a series of cryptic posts on social media. The influential investor’s widely anticipated ...

Shares of video game retailer and meme stock sensation GameStop plunged Friday afternoon and were throttled multiple times as the investor responsible for the craze behind them held a livestream.

GameStop (GME) shares have skyrocketed in the last month and a half, with Mr. Gill showing up with a gang of meme tweets to throw gasoline on the fire. There were even rumors that he is being ...