WARG (THE LORD OF THE RINGS)
Wargs were a breed of wolves in Middle-earth who lived in the Misty Mountains and were captured and used especially by orcs of Isengard and Mordor in the Third Age. Though wargs are not specifically evil themselves, they are almost exclusively bred by orcs. They were used by orcs as a form of transportation, in the same manner that men and Elves used horses. They appear first in The Hobbit, attacking Thorin and Company as they traveled east from the Misty Mountains.
In The Fellowship of the Ring, wargs attacked the Fellowship as they traveled to Moria. That they were wargs, and not ordinary wolves searching for food, Gandalf remarked, was evident from the fact that their carcasses were not to be seen the next morning.
Later, during Theoden’s retreat to Helm’s Deep in Rohan, a scout reported that “wolf-riders” were abroad in the valley, but wargs were not specifically mentioned.
In T.A. 2941, the wargs appeared once to meet the goblins and organize a raid on the nearby villages, in order to drive the woodmen out and capture some slaves. As a pack of wargs approached east of the Misty Mountains to meet them, Bilbo Baggins, Gandalf, and Thorin and Company were escaping the goblins. Gandalf, seeing the pack coming, suggested to climb the trees and Dori helped Bilbo just in time.
The wargs, thinking that the Dwarves were allies of the woodmen, surrounded the glade and didn’t let them descend. Gandalf then used his magic to light up pine-cones and hurl them against the wargs, until they were driven out. The wolves that had caught fire fled into the forest and had set it alight in several places, since it was high summer, and on this eastern side of the mountains there had been little rain for some time. However the guards left under the trees did not go away. Eventually goblins showed up and lit the trees the dwarves were hiding in, until the eagles came to rescue them.
In TA 3019 on January 13, the Fellowship of the Ring was attacked by a group of wargs. These wargs were presumably sent by Saruman to waylay the Fellowship after their failed attempt to cross the Redhorn Pass. The wargs fled after their first assault, but came back with reinforcements. Eventually, this second assault also failed, and the wargs fled again. Under the cover of night, the wargs dragged the bodies of their fallen comrades away from the site.
In the books, wargs are described as being giant, intelligent, and malevolent wolves.