Black Hole

Black Hole is a Mastery skill that was introduced in Reaper of Souls.

In-game
Black Hole pulls in all enemies in range (counts as Knockback), briefly preventing them from all actions, and deals massive damage over time in that area. It is a useful skill to use in conjunction with and/or Strongarm Bracers.

Runes

 * Supermassive: increases the Black Hole radius to yards and damage to  over 2 seconds. Damage type turns into Lightning.
 * Absolute Zero: each different enemy hit grants the Wizard increased damage for all Cold spells for 10 seconds. Black Hole’s damage turns into Cold. The effect is stacking infinitely, but a new cast overrides the already acquired stacks. Effect is increased to 5% on consoles.
 * Event Horizon: the Black Hole also absorbs enemy projectiles and enemy-spawned objects (including monster affix objects) within yards.
 * Blazar: after the Black Hole disappears, an explosion is unleashed for damage as Fire within  yards. Black Hole’s damage turns into Fire.
 * Spellsteal: enemies hit by Black Hole deal reduced damage for  seconds. Each different enemy hit by Black Hole grants the Wizard  increased damage for  seconds. The second effect stacks infinitely, but a new cast overrides the already acquired stacks. Both effects last 10 seconds on consoles.

Non-rune enhancements

 * Jang's Envelopment (Legendary Belt): enemies hit by the Black Hole are also slowed by 60-80% for 3 seconds.

Trivia



 * A black hole is an astronomical term used to describe a celestial object so massive that no nearby matter or radiation can escape its gravitational field.


 * The names of the ability's skill runes are also related to astronomy: Supermassive refers to the largest size of black holes, absolute zero refers to the lowest possible temperature, the event horizon is the radius at which the black hole's gravitational pull exceeds the speed of light and makes escape impossible, and a blazar is a type of highly variable active galaxy built around a supermassive black hole.
 * A very similar Physical damage skill is used by Kurekas in battle.