Shares of meme stocks surged Thursday following a cryptic post by Keith Gill, known as Roaring Kitty. Gill posted a mock Time magazine cover referencing the 2006 "You" Person of the Year issue, sparking speculative trading. Unity Software shares, ticker "U," rose nearly 5%, while Clear Secure, ticker "YOU," fell nearly 1% after early losses were pared. Gill's post drove increased call option activity, particularly for Unity. Traders also made complex options trades on Clear Secure.