Garthims from the movie
The Dark Crystal
Garthim are the loyal soldiers of the Skeksis. They appear to be Golem-like creatures that are animated through the power of the dark crystal. When the dark power of the crystal was healed the Garthim fell apart to reveal nothing but hollow shells. They were probably created by the Skeksis themselves after the shattering of the crystal to serve and protect them. The Garthim were used by the Skekses to carry out genocide against the Gelfling race.
The Garthim are insect-like resembling large beetles or crabs. They have thick shells which protect them from all but the most brutal of blows. However they also appear weak to magical weapons. Jen managed to fight off a Garthim by stabbing its claw with the crystal shard. In the "Legends of the Dark Crystal" Manga, Lahrdiscovered that Garthim could be killed by attacking weak spots in the armor with weapons.
The Garthim have little to no intelligence and follow all orders given by the Skeksis. They willingly followed the orders of the Chamberlain even after he was exiled. They are however aware of a command structure between the Skeksis and will follow the orders of the emperor above all others.
They can also be commanded by the mystics, to a limited capacity. This is probably due to the link that the Skeksis and Mystics share.
The main function of the Garthim is to raid Podling villages and collect them for slavery. (wikia)