Skin of the Great Sandworm

Skin of the Great Sandworm is a Brood of Nozdormu armor token. It can be exchanged along with various idols and scarabs at Kandrostrasz inside the Temple of Ahn'Qiraj for the following items:
 * Avenger's Legguards
 * Striker's Leggings
 * Stormcaller's Leggings
 * Doomcaller's Trousers
 * Genesis Trousers

Source
This item drops from Ouro in the Temple of Ahn'Qiraj.