An icelandic professional strongman plays a character nicknamed "The Mountain" in what series of novels?
Hafþór Júlíus Björnsson: Hafþór Júlíus "Thor" Björnsson (] ; also Hafthor Julius Bjornsson, born November 26, 1988) is an Icelandic professional strongman, actor, and former professional basketball player. Gregor Clegane: Gregor Clegane, nicknamed "The Mountain That Rides" or simply "The Mountain", is a fictional character in the "A Song of Ice and Fire" series of fantasy novels by American author George R. R. Martin, and its television adaptation "Game of Thrones".
A Song of Ice and Fire