The subject of this article or section originates from non-canonical sources. To find out about what is considered "canon" see LOTR:Canon.
The Guldur War Trolls, also known as Misty Mountain Trolls, lived most of their lives near the High Pass in the Misty Mountains. With their outstanding bulk they tower over normal Trolls, and yet they have some visual qualities of Orcs.
Portrayal in adaptations
Peter Jackson's The Hobbit: The Battle of the Five Armies
As with "Guldur Olog-hai", these trolls are exclusive to the 2014 film. Being much larger than the average Troll and extremely hard to take down, they are some of Sauron's greatest weapons of war. Their origins are not specified.
In the film, some ventured into the lair of the Goblins to get away from the sun. However a single group of them followed the goblins to Dol Guldur and fought in the Battle of Five Armies. They are first seen with catapult mechanisms on their backs and Goblins operating it, in which they proceed to launch catapults at the the ruined city of Dale. They were all wiped out during later stages of the battle. Their leader was an Ogre who lifted his club in the air and brought it down hard, signaling the trolls to fire the catapults.
In the extended edition, Azog commands his lieutenants to "Send in the War Beasts" and a group of trolls charge out of the tunnels but are quickly shot down by Elven archers and Dwarf chariots. Alfrid Lickspittle's death is caused by a catapult mounted on top of a Guldur War Troll, as Alfrid is stuck in the catapult, he drops a coin on the lever which launches him into another War Beast, killing the troll and Alfrid.
Earlier, a Guldur War Troll is flipped onto his back, causing the catapult to activate, launching him into the sky, then landing on a pile of Orcs.