A bug fix to a powerful Barbarian skill in combination with the Barber's near-infinitely scaling effect has one of the weakest classes now dealing over one billion damage to the hardest boss in the game, Uber Lilith, and killing her in under 30 seconds.
The Caged Heart of the Barber works like this: When you deal a critical strike on an enemy, any damage you deal after is soaked up (without affecting the enemy's health), amplified by up to 60%, and, after a few seconds, explodes as AoE damage. If the bottled damage exceeds the health of the enemy, it will trigger the effect so you don't have to wait for it to die. If you happen to critically strike other enemies during this, they too will begin the effect, and any explosions that go off during that get incorporated—which means the damage you deal will continuously be increased until everything is dead.
Patch 1.1.1, which dropped yesterday, fixed a bug with the Barbarian's Legendary Aspect of Berserk Ripping that prevented it from applying bleed damage over time to your target. The patch also secretly fixed how certain skills interact with the Barber.
Berserk Ripping now properly applies the bleed, and the Barber damage window now correctly scales the damage of those bleeds. As a result, you can trigger the Barber's effect then stack so many bleeds within it that Uber Lilith's health bar jumps up and down—almost like she's panicking over what's about to happen—before the final explosion deletes her.
The only drawback to the Barber is that Blizzard just nerfed an exploit that allowed players to endlessly farm a boss who could routinely drop it. But it's still fairly easy to farm by completing Malignant Tunnels normally. If you can hit level 70 and crack into World Tier 4, the Barber should be your top priority.
Other classes with on-hit skills, like Rogues, benefit from the hidden bug fixes to the Barber, but the Barbarians are the only ones who went from being able to deal some of the lowest damage output in the game to dealing damage that rivals the most powerful classes in the game. The interaction with the bleeds doesn't seem like a bug, but it might be far too powerful for Blizzard to let it go for too long. So have your fun while it lasts, Barbarians.