I finally defeated this evil thing!
I used an Unborn Valkyr and two Rapana Whelks
Here is what I did and yes, it took a few tries due to insane RNG
Unborn Valkyr first
1) Shadow Shock
2) Shadow Shock
3) Pass <- make sure to do this
4) Unholy Ascension <- make sure to click this as you are about to get killed
5) Curse of Doom <- If all went well you get a free ability when you rez... then you die again
If the above didn't work on your valkyr as in you died too soon, forfeit and start again.
Next comes the Rapana Whelk #1
1) Acidic Goo
2) Ooze Touch
3) Dive <- Curse of doom should be going off right about now
4) Ooze Touch
5) Ooze Touch if you aren't dead yet and repeat until dead
Finally and if you got lucky with the magically RNG fairy, this nasty should be around 800 health or so
Last comes the Rapana Whelk #2 and a repeat of #1
1) Acidic Goo
2) Ooze Touch
3) Dive
4) Ooze Touch
5) Ooze Touch and repeat if you haven't won yet
Again, this is going to take a few shots but it works and is a lot less stressful than other pets.
Oh and Fire Quills need to be nerfed like yesterday!