WATCH: Conor McGregor Sparring With ‘The Mountain’ From Game Of Thrones Posted by Ruairi O'Mahony June 7th 2017, 13:59 I guess there is a reason for weight classes in the UFC. No matter how good McGregor can get, I have a feeling, Hafþór Júlíus Björnsson has the upper hand. Watch their sparring session here:https://i.imgur.com/6GGOdm0.mp4