Devour

Devour is a Corpse skill in Diablo III. It very loosely resembles the Carrion Vine and Solar Creeper.

In-game
When cast, consumes all nearby monster corpses (radius is wide enough to affect the entire screen) to replenish the Necromancer's Essence.

Corpses are not devoured all at once, but rather in rapid succession, roughly 3-4 per second.

The skill costs no Essence to cast, and has no cooldown, so with sufficient corpses, it can be used again and again.

Runes

 * Satiated: Increases maximum Life by for  seconds for each corpse devoured. Current Life increases proportionally; the absolute value of current Life does not decrease when maximum Life is returned to normal value.
 * Ruthless: Also consumes all of the Necromancer's minions for additional Essence per minion killed.
 * Devouring Aura: The skill can no longer be cast, and instead becomes a passive aura that consumes all corpses within yards of the Necromancer, restoring  Essence per corpse. The range of this effect is increased by  of effective gold pickup radius. The skill will show a faintly pulsing aura displaying the radius.
 * Voracious: Reduces all Essence costs by for each corpse consumed for  seconds. This effect stacks from multiple casts, up to 50 times.
 * Cannibalize: Each corpse consumed also restores of maximum Life.

Non-rune enhancements

 * Requiem Cereplate (Legendary Chest Armor): Devour restores an additional 75-100% Essence and Life, and when Devour restores Essence or Life above the maximum, the excess is granted over 3 seconds instead of instantly.
 * Corpsewhisper Pauldrons (Legendary Pauldrons): Corpse Lance damage is increased by 25-30% for 3 seconds for each corpse consumed by any skill, stacking up to 20 times.
 * Trag'Oul's Avatar Set (Set Bonus for 4 items): while at full Life, healing from Cannibalize is added to maximum Life for 45 seconds, up to 100% additional Life.
 * Trag'Oul's Avatar Set (Set Bonus for 6 items): healing from Cannibalize is increased by 100%.
 * Pestilence Master's Shroud Set (Set Bonus for 2 items): each corpse consumed fires a Corpse Lance at a nearby enemy.
 * Pestilence Master's Shroud Set (Set Bonus for 6 items): each corpse consumed grants an Empowered Bone Spear charge that increases the damage of the next by 3300%. Can store up to 100 charges, each cast consuming 1 charge.

Passives

 * Fueled by Death: grants 3% increased movement speed for 5 seconds, stacking up to 10 times, for each Devoured corpse.
 * Life from Death: each Devoured corpse has a 20% chance to create a Health Globe.

Development
The logic behind the Necromancer's Devour skill was that though it can feel wasteful, the decision to consume all the corpses is intentional, so Devour isn't used mindlessly.