Submastyx hide is a tier 2 Dungeoneering hide used to make Subleather armour by using a needle on it while having thread in your inventory. As with all Dungeoneering hides, no tanning is required before these can be made into armour.
Players can obtain the hide either by hunting or killing a Submastyx or buying it from the Smuggler. Trapping is the more efficient method to gain hides instead of outright killing as more hides can be obtained while killing it may actually result in no hides. However, this option is only available to members.