Basically all you need from this pet.

• the 2 open slots are ment for whatever you feel like you want have extra off.
• Personally I am not a big fan of [Viral Quills], it is a waste of a mod slot.
  Only case I saw it somewhat useful is if I had absolutely no source of viral on anything but even then the 4 seconds cooldown make it annoying more then useful.

3 Forma options with Madurai polarity:

If you will be using Bite/[Maul] I would Recommend dropping one of the Synth mods for [Hunter Recovery]. You can go further and drop Synth mods entirely and go for [Swipe] as it will increase the healing output dramatically.

if you will be using pet for utility more then anything else you don't need more than 3 max.
Anything above it is just a waste of forma you can use on something else.