Wrath of the Berserker

Wrath of the Berserker is a Rage skill.

In-game
When activated, changes the appearance of the Barbarian, turning them into a giant with molten skin and pale hair. While in this form, the Barbarian is liberated from and made immune to all forms of Crowd Control, retains all their usual skills, and gains the following attribute bonuses: These buffs are not multiplicative to other similar effects.
 * Critical Hit Chance:
 * Attack Speed:
 * Chance:
 * Movement Speed:

Runes

 * Arreat's Wail: also deals damage as Fire to all enemies within  yards of the Barbarian when activated.
 * Insanity: also increases all damage done by for the duration, not multiplicative to other similar effects.
 * Slaughter: while active, Critical Hits have a chance to create an explosion of blood on the target, dealing damage as Physical to all enemies within  yards of the victim.
 * Striding Giant: also reduces all damage taken by the Barbarian by for the duration.
 * Thrive on Chaos: also grants additional Life per Fury spent for the duration. The amount of Life per point of Fury spent scales with level, up to at level 60 and  at level 70.

Non-rune enhancements

 * Mortick's Brace (Legendary Bracers): gains the effect of all skill runes.
 * Halcyon's Ascent (Legendary Amulet): upon activation, causes nearby enemies to jump uncontrollably for 6-8 seconds.
 * Remorseless (Legendary Mighty Weapon): while both Wrath of the Berserker and Call of the Ancients are active, Hammer of the Ancients deals 200-250% more damage.
 * Immortal King's Call Set (Set Bonus for 4 items): Wrath of the Berserker remaining cooldown is reduced by 3 seconds for every 10 Fury spent.
 * Immortal King's Call Set (Set Bonus for 6 items): while both Call of the Ancients and Wrath of the Berserker are active, the Barbarian deals +4000% increased damage.

Passives

 * Boon of Bul-Kathos: reduces cooldown by 30 seconds.

Development
Originally, Thrive on Chaos rune was prolonging the duration by 1 second for every 25 Fury spent. However, this was making it the best possible choice (as WotB form could be sustained infinitely), and in Patch 2.0, it was changed.

Trivia

 * The appearance change of the Barbarians during their berserker form may be a reference to or inspired by the Super Saiyan forms from the Dragon Ball franchise and/or Augus from Asura's Wrath.
 * This is the Barbarian's transformation skill which boosts powers and changes appearance, each class (barring the Witch Doctor) has one and all of them give the added bonus of immunity to Crowd Control; the other class equivalents are: Vengeance (Demon Hunter), Akarat's Champion (Crusader), Epiphany (Monk), Land of the Dead (Necromancer), and Archon (Wizard).