The Age of Worms
Talisman of the Sphere
Used to control a sphere of annihilation. These spheres first surfaced during the Chaos War, and both sides had to control them. If they are moving, they will just keep destroying.
The party specifically possesses one used to control a sphere that destroyed Zosiel. Riddle can also use it to focus his divine energy, though not being an arcane spellcaster, he cannot actually touch it to do so.