An argument can easily be made that putting heavy plate armour on a man with the dimensions of Gregore Cligane is beyond ludacrice however the suit that was constructed for this character in Game of Thrones was not only well suited, but it also one of the most practical suits of armour on the show.
Ser Gregor Clegane aka: the Mountain tops out at 6 foot 7 feet tall and easily 300 lbs solid. He is an imposing landmass of a man. He could be wearing his pyjamas and still make you shit your pants. However, they have designed and built for him suit of armour that offers maximum protection and maneuverability. The base, depending on which you look at as the two primary suits are very similar, consists of a heavy 6 into 1 chainmaille tunic and battle skirt with leather and cold forged steel plating. The breast plating is sectional allowing for added range of motion. The yolk and gorget are triple layered and hardened solid. An impressive 4 layer folded steel spaulder tops each arm with chainmaille and leather sleeves lay under the equally impressive layered gauntlets. The grieves are the only plate armour pieces on his legs but the battle skirt, being so hefty, offers not only the ability to block any hit but it being loose from the body makes it highly unlikely that he would even feel the hit.
His helmet may leave something to be desired esthetically as it is merely the old English bucket style with slit narrow visors but it is padded. It is solid and the curves and cold riveting have the natural ability to deflect any blow. No weapon would be capable of finding a surface to strike evenly. It would simply find an angle and glance off.
The overall finish of the piece is something rarely seen in cinematic ventures such as this in that it’s not new. It is not shiny and perfect. It is black over cobalt steel and it is battle damaged and aged beautifully indicating that this man loves to fight. A terrifying prospect.
Overall, the functionality of this armour completely out weighs the esthetic. This is a true testament to function over form to spite the fact that no one other than the actor playing Ser Gregor could possibly move in the damn thing with it being so heavy.
Who wears your favorite armour on the show? The crows? Ned Stark? Tywin Lanister perhaps?