The subject of this article originates from non-canonical sources. To find out about what is considered "canon" see LOTR:Canon.
Appearing only in The Lord of the Rings: The Battle for Middle-earth strategy game series (and not in Tolkien's writing), a Giant Scorpion was a rare arachnid monster, much like a Giant Spider. In the game, Gorkil the Goblin King rode one. Although unlikely, other Goblin Chiefs could have ridden these as well.