Wargs have a moulded and pre-assembled piece, exclusive to them, and come in white, gray and brown. They feature two points of articulation: the neck, and the lower jaw, and have a 1x2 cut-out in their backs to enable a saddle to be fit like a horse.
Wargs were giant, savage and deadly wolves who lived in Middle-earth, roaming Rhovanion, and the wilds to the east of the Misty Mountains. They were used in battle by orcs and Gundabad Orcs, instead of horses being used, as they were far stronger. Fell Wargs, used by Gundabad Orcs inhabited Rhudaur and Angmar; Wargs used by Isengard forces were found in Dunland.
In The Lord of the Rings: The Two Towers, Wargs of Isengard attacked the people of Rohan, while they were travelling to Helm's Deep. In The Lord of the Rings: The Return of the King, Gothmog rode a Warg at the Battle of Pelennor Fields.