These spiked armor shoulder pads are part of an ancient Shokan Armor, a war uniform worn by the tiger-like Shokan named Kintaro. This armor first originally appeared in Mortal Kombat II, and later reappeared, both with an updated version of itself, and also as one of the collectible Relics named Kintaro's Armor within the Konquest mode of Mortal Kombat: Armageddon.
Kintaro, who came from a tiger-like bloodline within the four-armed half-human, half-dragon Shokan race of Outworld, wore this armor in battle as he crushed his foes in the name of his Shokan heritage, and in his services as a royal bodyguard to Shao Kahn, Emperor of Outworld.
Kintaro's own Shokan Armor also appears with another updated version in Mortal Kombat (2011) alongside Kintaro's fellow Shokan Sheeva, who also wears the particular armor shoulder pads of Shokan design.
They also make an appearance in MK Mobile as an Equipment Kard named Bloody Shokan Armor.