One of the new bosses in the upcoming raid, Aberrus, uses a Class Calls mechanic similar to the Nefarian's Blackwing Lair encounter from Vanilla.
Neltharion Encounter Class Calls in Patch 10.1During Phase 2 of his encounter, Neltharion will Surrender to Corruption, dealing damage to players and then forcing one class to succumb to Corruption.
NEW Neltharion surrenders to the power of Voices from Beyond, inflicting Shadow damage to all players every 1 sec. for 10 sec., and a final 124889 Shadow damage to all players upon succumbing. Additionally, Neltharion will force a class to succumb to Corruption.This chosen class will have their spells corrupted allowing them to see adds called Voices from Beyond. However, as their spells are corrupted, each class will have a different effect when called upon causing them to negatively affect your allies. Use the Corruption to help kill the adds, but avoid killing your teammates with it!
Warrior NEW Neltharion drives the warrior into a Wild Bladestorm every 6 sec. for 30 sec, causing them to inflict 104,120 Physical damage to all players and creatures in 8 yards every 1 sec. for 4 sec. Paladin NEW Neltharion corrupts the paladin's faith, forcing them to unleash Zealous Hammers every 6 sec. for 30 sec, inflicting 124,833 Holy damage to all creatures and players that stand in their path. Hunter NEW Neltharion forces the hunter to call corrupted pets from their stable, forcing them to attack. On death, these beasts erupt with Unleashed Darkness. NEW The death of a creature summoned through Neltharion's manipulation of corrupted players explodes for up to 416298 Shadow damage to all creatures and players in 10 yards. Rogue NEW Neltharion corrupts the rogue's natural Read more on wowhead.com