Form of Restless Spirits  

As of the recent patch, our spectre pets now have a new graphic. It is the same as this spell. I looked around for the new pet illusion spells and found 3 of them in Blightfire Moors at the Outpost Camp in the middle of the zone. Undertaker Schell (loc -20, 482) sells Form of Bleached Bone - level 44, for less than 16pp; Form of Chilled Bone - level 16, for less than 5pp; and Form of Mottled Bone - level 56, for less than 17pp.

These spells don't overwrite each other but if you suspend minion it loses illusion and you see the spectre pet again. Yes, I have Suspend Minion II but it still loses illusion buff.