Curtis Fig  

This mob will rapid-fire between two modes, telegraphed by messages at the center of the screen. He will either become magic resistant or prepare for a leap attack. The leap attack is the spell Avenging Leap. It causes him to jump to another player character and attack them but since it doesn't cause aggro to outright reset it isn't that bad. The magic resistant mode means he activates two spells that place short duration buffs on him: Avenge Jorelia and Avenge Crellith. These go away so quickly that you might not even notice they were ever there.