A great Beast
From the very heart of the dark lands of Mordor, the great beasts, or beasts of Gorgoroth (Orc. "Bûs") are huge, strong creatures - many of which were captured by the Orcs for use on the battlefield. Whether hauling huge siege weapons, or carrying Howdas full of troops to battle, these huge beasts are a formiddable sight to behold, and it takes the bravest of warriors to be able to face on in battle.
A much smaller cousin of the great Beasts are the Iron-Hill-Beasts, used as beasts of burden and draft-animals by the Dwarves of Azanulinbar-Dum.