Unholy Infusion

I had a hard time pulling this off as a 100 Retribution Paladin, but then realized I was overthinking it a bit. I did this on 25-Man Heroic ICC.

1. 
   
2. Equip Shadow's Edge.
3. 
   
4. Pull Putricide and let him drop 3 puddles of ooze from Slime Puddle (I just kept pulling him straight backwards from his table, so he dropped them in a straight line).
5. 
   
6. Take his health down to about 82%. Do not hit 80% or he goes to Phase 2.
7. 
   
8. Once the ooze is down and his health is where you want it, walk over beside the table and hit him one more time to take him down to 80% (he'll start casting Unstable Experiment) and immediately right-click on the table to drink.
9. 
   
10. You'll turn into the Abomination while he's creating his concoction (keep an eye on his cast bar to see how much time you have). Run around in the ooze and spam 1 to fill up the ooze meter on the right of your vehicle display.
11. 
    
12. Keep doing so until the Axe icon lights up, then hit 6/click the icon to start casting Shadow Infusion (make sure you LET THE CAST COMPLETE). When the cast is done you'll see a "Shadow Infusion" buff on your character.
13. 
    
14. Kill Putricide.
15. 
    

I didn't have to do anything with Divine Shield, and I didn't have to kill the oozes. The key was getting him to 80% and then immediately drinking from the table while he was in mid-cast (before he even got to the table). His cast takes aggro off of you, and then when he goes to the table to make his concoction aggro stays off of you.

How to complete this SOLO, in the age of 110's, 840ilvl's, and Artifact weapons

I've tested this on multiple characters at this point. The only time I've had issues is when I've messed up. The good part is that if you do mess up, the fight simply resets and you can try again in about a minute.

Setup:

• 
  
• Set ICC 25: Heroic - This gives the boss as much HP as possible. You need control over phases, so it matters.
• 
  
• (Optional) Remove all gear EXCEPT [item=49888] - You obviously need the axe. Removing gear lowers your damage, and gives you control over his HP. There's nothing special about this, so if you need more gear, feel free. I've just found that it helps.
• 
  

Steps:

• 
  
• Engage fight. Do not hurt the boss below 80%. Lower him as close as you can (81-83% is good.) You have time to do this.
• 
  
• Kill oozes if you'd like. Leave one up if you're paranoid. Not required, but won't hurt anything.
• 
  
• Allow him to place ground poison three times in different spots.
• 
  
• Once three ground poisons are placed, verify boss's health is above 80%. Go to the middle of the room.
• 
  
• Wait.
• 
  
• Once the boss begins to cast an ability (look for a cast bar) - Burst him below 80%. Immediately run to the table and drink. You should transform while he is running. This is very important.
• 
  
• Run straight into the poison clouds. Mash your 1 ability to drink and restore energy. Use the shadow ability (6) at full energy.
• 
  
• Once complete, allow the abomination to die, and kill the boss. You can use another weapon, once you've completed the song and dance above.
• 
  
• Congratulations! On to the next objective.
• 
  

The issue with the fight is that it resets if the boss looks for a target and can't find one. This is, for the most part, a scan that enemy AI performs at a tight interval. When you transform, you can't technically be targeted for a very short amount of time. If the boss scans during this time, it won't pull a viable target, and the fight will reset.

To get around this, you need to push your short invuln window to a position where the boss isn't scanning. Sometimes you can get lucky, which is why some other methods work, sometimes. The only reliable method is when the boss AI is pacified. This happens when he's running back to the table.

When the boss is casting, he isn't moving. This is why you move him to the middle. By moving him to the middle, he will exit his cast and immediately begin running to the table, and have to cover distance in order to do so. This directly lengthens the pacification window during which the transformation can safely execute.

You hit the table during his cast in the center because the transformation does not happen right away. This gives you the biggest window to aim for with the delay involved.

As a note, I'm not sure exactly how the target acquisition works during his little table science routine. I've had it reset if I transform during this phase, so I'm sure he acquires targets at some points during it. Also, if you do wait for this cast, you run the risk of not surviving long enough in abomination form to completely charge your energy.

Hope this helps!

So from what I am reading from the boss abilities and the description in the quest objective, this is my theory about how you get this done.

Strategy: You become one of the abominations that will be eating Mutated Slimes. Since the quest text says "Find a way to absorb his mutated slime", this makes sense since you are technically obsorbing the slimes when you eat them. You will have a new button in your Abomination vehicle that says Shadow Infusion. This ability can only be used once you have gathered 100 energy in your Abomination vehicle, it should take between 30-60 seconds to gather the 100 energy. Based off the information below, it is recommended that you use the Shadow Infusion ability when the boss is around 40% health.

It is critical to notice the infusion buff only lasts 6 minutes. If you do not deteat the boss within the 6 minutes, you have to infuse the weapon all over again.

Update: Wing 2 (Plague Wing) is now live. Strat above has been updated to reflect actual strat. Thank you to the folks below who gave the details. =)