Troll (Discworld)
In Terry Pratchett's Discworld novels, the monstrous trolls of folklore and J.R.R. Tolkien have been subverted into a moderately civilised race. They are nocturnal, silicon-based creatures, hence the stories of them turning to stone when hit by the sun. Their apparent unintelligence is due to heat affecting the conductivity of their brains. In high mountain areas they can, in certain respects, be quite clever.
Troll society is based on rocks and hitting people. They have numerous gods, all of whom bless their worshippers by hitting them on the head with a rock. In a troll courtship the male troll hits the female troll on the head with a pretty rock. And so on.
Rock and stone is also the natural diet of trolls, and they have diamond teeth to enable this. They can gain some nutrition from the mineral content of carbon-based animals (including humans, although they never do that any more, honest), but not much. The troll language (like dwarfish) has hundreds of words for different kinds of rock. It also has one word that means "vegetation".
Trolls tend to be named after rocks, minerals and geological features.
Trolls and dwarfs have an ongoing feud, ostensibly stemming from one being a race of living rocks, and the other being a race of miners, but really, these days dwarfs hate trolls because trolls hate dwarfs and vice versa.
Troll society is unsophisticated, but some trolls in urban areas such as Ankh-Morpork manage to direct their tendency towards violence in more civilised directions. Many trolls have joined the City Watch, beginning with Sergeant Detritus. Others have found a niche in the opposing profession; there is a troll organised crime family, called the Breccia, led by the "Ton" Chrysophrase.
Trolls are theoretically immortal, but as they get older they get bigger and slower and tend to be more inclined to sit and think. They call this "getting philosophy". Many of the Discworld's mountains are actually very old trolls.
According to The Discworld Companion, there exist, in addition to humanoid trolls, troll dogs, horses and ducks (although the ducks tend to sink a lot). However, none of these have been seen in the novels thus far.
