Ukhrâsh
Ukhrâsh are a breed of large, crab-like animals that lurk deep below Mount Gundabad. While technically crustaceans, they are classified as part of the Spiders and Insects category (their closest relations among the creatures of Middle-earth). In the centuries since the Dwarves abandoned Mount Gundabad, the mountain has become inhabited by many dangerous beasts. The Ukhrâsh were discovered by the Gabil'akkâ during their attempts to reclaim the Mountain-home and the creatures have proven to be a persistent nuisance. However, a few hardy adventurers have managed to tame certain Ukhrâsh and have even kept them as pets.
Ukhrâsh can be found in underground lakes such as the Gloomingtarn and various smaller bodies of water in the Pit of Stonejaws.
Background
Ukhrâsh do not appear in the work of J.R.R. Tolkien. They were created for The Lord of the Rings Online.