Cloaking spheres are magical objects used by officials of the different sanctuaries to turn themselves or people/objects around them invisible. They consists\ of a small ball with two distinct halves that can be twisted away from each other/spheres to form a "bubble" of invisibility that can be adjusted to match the size of whatever the user wishes. It was mentioned by Skulduggery in the first book, when he takes Valkyrie into the Repository for the first time, that they are rare to find, and most of them are in the possessions of the Sanctuaries around the world.
A Cloaking sphere is used in the Kingdom of the Wicked.
A Cloaking Sphere is used at the French Sanctuary when Valkyrie steals The Engineer. Another is used When Skulduggery and Valkyrie sneak into the English Sanctuary to kidnap Cothernus Ode. Another is used by the Supreme Council to sneak up on the Irish Sanctuary during the battle at the Keep. One is used during the battle of Roarhaven when General Mantis and his squad attempt to assassinate Charivari.