Piercing Wail: huge frontal AOE with unlimited range. Everyone, including tanks, has to joust this one. The spell stuns/stifles for 2 minutes and deals significant damage. There is a text announcement at the first cast, but not thereafter.
Crippling Aura: every hit on the tank increases the damage they take by 10%, growing exponentially higher after 10 increments. Swapping tanks is required to deal with this detriment.
The arcane disruptors are adds that spawn throughout the fight and must be burned down promptly. The add tells the raid "You dare not slay me, lest I curse all casters near!" and appears to cast a spell called Arcane Dampening. The arcane disruptors can only be damaged by melee, and the script includes a fail effect.