“Star Wars” icon caused chaos in the Twittersphere over the weekend when he simply tweeted his own name and it instantly went viral. Hamill, 69, was challenged by a fan (@LozzaBean12) to “just tweet ‘Mark Hamill’ and you’d get thousands of likes.”To which the actor responded, “Mark Hamill.” Surely enough, since he tweeted Sunday evening, the tweet has been liked almost 560K times and has nearly 30K retweets.