Watch 'The Mountain' from 'Game of Thrones' Break a 1,000-Year-Old Weightlifting Record

You might not recognize the name Hafthor Julius Bjornsson, but you probably know him by his other name: The Mountain.

Bjornsson joined the cast on last season of "Game of Thrones" as the Mountain, taking over for another actor who had played the role briefly in previous seasons. In doing so, he became part of one of the most talked-about scenes of the entire series thus far, as the Mountain took on Oberyn Martell to decide Tyrion Lannister's fate.

Bjornsson, as his character's name indicates, is huge. He's 6'9" and weighs nearly 420 pounds, and we're pretty sure 80% of that is muscle. He's won all kinds of strongman competitons in the past, but he just recently broke a 1,000-year-old viking record.

There's a video circulating of Bjornsson winning his second "World's Strongest Viking" title in a row by lifting a log and walking five steps while carrying it. That might not sound like much, but here's the catch: the log weighs 1,433 lbs.

That's a world record, one that hasn't been set since the viking days over 1,000 years ago.

And that, friends, is why you don't mess with The Mountain.

Check out the video below: