Bone 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' in World of Warcraft 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. Many video games also feature spiders made of bones or skeletons which acquire this form (such as Castlevania) and are often considered very disturbing and scary.