I discovered this in patch 2.3.0 so I'm not completely sure if this still works, but the patch notes said nothing about this. I'd also like it a lot if someone could test this in patch 2.3.3.
Things you will need:
Eye of Arachnida - Thottbot World of Warcraft: Eye of Arachnida
A karazhan raid
Step 1: Summon your eye of killrogg using Eye of Arachnida.
Step 2: Bring him to moroes and let him kill it.
Step 3: Enjoy fighting moroes with no adds.