Mountain Troll

Mountain Trolls (Orcus Troglodytarium Alpinium) are a species of troll semi-sapient humanoids.

Physical Description
Mountain Trolls stand up to twelve feet tall, and can weigh over a tonne. They have a small, bald head with oversized ears, two toes on each foot, and greyish skin. Trolls emit a peculiarly unpleasant smell.

Behaviour
Mountain Trolls are only debatably sapient, although the smarter ones can sometimes manage to reach the level of very dim-witted human beings. They are often aggressive, as many wild trolls do not see other sapient beings as anything else than prey. Mountain Trolls have been known to forcefully tame Graphorns  and use them as mounds. Their weapon of choice is a large wooden club.

Lifespan
Although it is speculated that Mountain Trolls' lifespans could theoretically reach that of a muggle human beings, their uneven diet and lack of hygiene mean that most Mountain Trolls die at around fifty years old (even discounting the tremendous amounts of fighting they perform, which often does them in much earlier).

Magical Abilities
Trolls have no active magical abilities. However, latent magic makes their skin highly spell-resistant, and this magical capability also allows their whiskers to be used as wand cores (though they are considered an inferior core material).

Habitat
Due to Goblins breeding Mountain Trolls as subservient grunts for their minework and defenses, and therefore bringing them all over the world in the process of their financial expansion, Mountain Trolls, who are thought to have originated in the Carpathian Mountains, have spread out to most mountain areas all over the globe, though they prefer colder climates.

14th Century
In the 14th century, the Dark Wizard Alexander Nadroj captured Mountain Trolls and tried to warp them using magic into useful soldiers for his armies. His experiments resulted in the birth of a new subspecies of trolls, the Trolls of Nadroj, whose distinguishing features were oversized, clawed hands. It is believed that the escape of other experiments of Nadroj's and their subsequent inbreeding with wild trolls is responsible for some peculiar traits found in some trolls, such as some Forest Trolls having more than two toes and River Trolls sometimes having horns.

16th Century
In the 16th century, a colony of Mountain Trolls began terrorizing Liechtenstein. The local wizards resorted to increasingly murderous devices to get rid of the raiding barbarians, which resulted in then Chief Mugwump Pierre Bonaccord banning all troll-hunting and firmly establishing the French position that Trolls should be given rights due to their sapience. As a direct consequence of this decision, Liechtenstein pulled out of the International Confederation of Wizards, so that Bonaccord's decision not affect them. The Troll Colony was slaughtered down to the last trollling soon afterwards.

20th Century
In the 20th century, British wizard Quirinus Quirrel developped a peculiar talent for handling trolls, and was able to turn at least two, Mohump and Gareg, to his service (and, by extension, to that of his master, Lord Voldemort). The first one he smuggled into Hogwarts School of Witchcraft and Wizardry in Halloween, 1991, as a distraction for his attempt at stealing the Philosopher's Stone. Mohump was subsequently disposed of by Harry Potter, Hermione Granger and Ron Weasley (who used a Levitation Charm to drop Mohump's own club on his head) after he attempted to smash Hermione in a fit of rage. Quirrel brought his second troll, Gareg, legally, using him as one of the protections for the Philosopher's Stone. Unexpectedly for Quirrel, Gareg, taking his task too seriously, refused to budge when Quirrel attempted to pass himself. He was subsquently knocked out by the wizard.

British Ministry of Magic Classification
Due to the majority of Trolls' inability to understand wizarding laws, Mountain Trolls are classified as Beasts, and given the XXXX threat level.

French Ministry of Magic Classification
In the French classification, Trolls are classified as "Êtres Sauvages" (Wild Beings).

Canon

 * Mountain Troll on the Harry Potter Wiki