You may not know Halfthor Bjornsson by name, but you probably know him by frame—the 6'9", 419-pound frame that plays Gregor "the Mountain" Clegane on HBO's Game of Thrones. He won Europe's Strongest Man in 2014 and 2015, and was runner-up in World's Strongest Man in 2014. And yet, he can't beat a guy almost 200 pounds lighter than him in arm wrestling. That's because the 225-pounder in question is Devon Larratt—formerly of the Canadian Special Forces and now a two-time WAL heavyweight arm wrestling champion.