Ever wondered how the top 5 WoL DPS for this fight are mages with over 360k+ dps?
When the boss reaches 70% health it transitions into phase 2 of the encounter and the boss casts Amber Carapace onto himself and takes 99% reduced damage. The boss will then spawn Amber Monstrosity.
If a mage builds up a nice ignite and uses combustion just before the boss takes 99% reduced damage, he can then spread the combustion onto the Monstrosity. For some reason when the dots from the boss are spread onto other targets the dot damage gets multiplied by x99 and the Monstrosity is then taking 2.5m non crit (5.7m crit) combustion damage ticks while ignite and other dots are also doing insane damage. We did this tonight with 4 mages in the raid and the Monstrosity was killed within 15 seconds which basically removed phase 2 from the encounter.
If you skip to 3:40 and watch Recount, you see the mages peak at nearly 500k DPS.