Hafthór Júlíus Björnsson is an Icelandic professional strongman who made a name for himself playing the brutish Gregor Clegane on the HBO series “Game of Thrones.” While visiting Ireland, Björnsson stopped by the Straight Blast Gym for a sparring session with UFC interim featherweight champion Conor McGregor. 

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Luckily for McGregor, Björnsson decided not to do what he did to Oberyn Martell back in back in Season 4. 

A photo posted by Hafþór Júlíus Björnsson (@thorbjornsson) on Oct 30, 2015 at 11:48am PDT

(Warning: Video contains VERY graphic violence)