Death Cloud is the uncontested flagship of Mage damage spells, combining all of the offensive abilities of every Mage spell into one single devastating projectile.
The Death Cloud projectile has inherent homing abilities and a very large explosion radius. Mages wielding this power would be wise to make sure the area is clear, because getting hit with one's own Death Cloud is a very bad idea. Fortunately, the projectile is rather slow, so there is time to run after firing one.
Each hit deals 10 electric, 5 fire, 5 poison, 5 drain, and 5 piercing damage, as well as applying a 5-strength poison.
At 20 mana per cast, the damage efficiency of this spell is 1.5 dpm.
Death Cloud is available to all classes via the Wand of Death, though it's unlikely any but the Priest and the Mage will have the mana to effectively use it.