GameStop’s sales may have taken a hit from the coronavirus pandemic, but its stock price has surged roughly 400% since the year began thanks to an “ugly” fight prompted by day traders on a Reddit investing thread.

After closing Friday at roughly $65 per share, shares of GameStop surged on Monday morning to more than $140, even prompting the New York Stock Exchange to issue a temporary pause on trading the stock four minutes into Monday’s session, according to the Wall Street Journal.