TL;DR Always kill purple. After that, kill priority is green > yellow > blue > black > red.
And now, the long explanation:
There are seven slimes that can be summoned. The boss will summon three at a time. You must kill one and leave the other two up (as once you kill one, the others become immune to attack). Sort of like Halfus, Yor’sahj’s abilities depend on which slimes you don’t kill. The abilities each slime grants are as follows:
- Purple – Stacking debuff that will kill you if you receive too many heals.
- Green – Does AOE damage to the raid based on player distance to each other. Closer than 4 yards means death.
- Yellow – Decreases the bosses attack/cast time by 100%. He now does everything twice as fast.
- Blue – Depletes all caster’s mana. Stolen mana is returned upon death of the mana void add that spawns.
- Black – summons numerous adds that must be AOE’d down.
- Red – Does AOE damage that increases the more spread out the raid is.
- Healing Limited (Purple, Blue) – These slimes prevent heals from working effectively.
- Heavy Raid Damage (Green, Yellow, Red) – These slimes greatly increase the amount of damage your raid is taking.
- Fast DPS Required (Black, Blue) – These slimes require the players to stop tunneling the boss and instead focus on killing adds.
My kill priority: purple > green > yellow > blue > black > red is explained as thus:
- Purple = death incarnate
- Green = we’re too lazy to turn on range check and spread out properly
- Yellow = double attacks hurt a lot, no fun for heals. Use shamanistic rage on this one.
- Blue = There’s nothing more dangerous summoned? Oh, ok then. I guess we can let the mages have mana too.
- Black = Always up, since something gets killed before it. AOEing adds is no trouble for us, and the warrior wants an excuse to use his Whirlwind/Bladestorm macro
- Red = Drop stoneclaw. DPSDPSDPSDPS