A race of monstrous creatures found in caverns and dark places. They are known from an encounter with the Fellowship of the Ring as they passed through Moria, but were evidently found elsewhere in Middle-earth, too. These trolls, along with Orcs and perhaps other creatures, were originally sent to inhabit Moria by Sauron some five hundred years before the War of the Ring.
The cave-trolls of Moria were of huge size with a skin of dark green scales, and flat, toeless feet. The fact that Gandalf was able to recognise the creature he encountered in Moria specifically as a cave-troll strongly suggests that this appearance was shared by others of the kind.