Bone spider



Bone spiders or plagued spiders are a unique type of spider that appear to be made up completely of bone. Originally, they were introduced in 'Wrath of the Lich King' and could only be found in Northrend in the zones of Icecrown, Zul'Drak, Azjol-Nerub, and Ahn'kahet: The Old Kingdom. These creatures are already undead when they hatch.

The pale of the Howling Crag are known to turn into bone spiders by using the Ritual of Siphoning.

Northrend

 * Bone Spiders are summoned by Khit'rix the Dark Master in Icecrown.
 * Carrion Fleshstrippers are found in the Valley of Echoes in Icecrown.
 * Deep Crawlers are found in Ahn'kahet: The Old Kingdom.
 * Necrotic Webspinners are found in Icecrown.

Outside of Northrend

 * Ashweb Weavers, Ashweb Piercers and Ashweb Hatchlings are found in the Ruins of Guo-Lai in the Vale of Eternal Blossoms. Their matriarch is Bloodtip.
 * Battle Creepers are used by the Forsaken dark rangers in the Hillsbrad Foothills. They appear to be trained Domesticated Mine Creepers that are found in Azurelode Mine.
 * Bloodtip Swarmers are baby spiders who appear during the battle against Bloodtip.
 * Bone Spiders are critters found in Mogu'shan Vaults.
 * Corpse Spiders are found in the Refuge Disposal of the Throne of Thunder
 * Darkweb Devourers appear in the Deadmines, during the encounter with Helix Gearbreaker.
 * Darkwood Lurkers and broodmothers are found on the Tol Barad Peninsula.
 * Desert Spiders are critters found in Uldum.
 * Dreadspinners, Dreadspinner Hatchlings and Dreadspinner Tenders can be found in the Dread Wastes.
 * Festering Spiderlings and Plague-Rotted Webslinger are found in Razorfen Downs.
 * Silkwood Stalkers are found in Silkwood in The Jade Forest. Their younglings are Infant Spiders.
 * Skitterweb Spiders are found in the Skittering Dark of Silverpine Forest. The appear in the lurker, matriarch, spiderling and striker varieties.
 * Tainted Nightstalkers are found in the Blasted Lands.
 * Weeping Widows and Widowspawns are found in Widow's Wail in The Jade Forest.

Alternate Draenor

 * Boneshallow Spiders are found in the Ashmaul Burial Grounds in Ashran.
 * Deathweb Spiders are found in the Deathweb Hollow of Talador. The appear in the hatchling and crawler varieties.

Named

 * 

As a companion

 * Dusty Clutch of Eggs can be looted on Maexxna in Naxxramas.

Speculation
These creatures are possibly related to the nerubians who are part of the Scourge.
 * Nerubian relations

Bone Spiders may be the bane spiders referenced in the Manual of Monsters.
 * Bane Spider