The Rk. II version of this spell summons a lvl 85 pet; it procs "Spectral Lifetap" for 285 damage which has a 5% chance to also proc "Prism Skin", a buff common to Mage and Beastlord pets (from their pet's proc buffs). The previous pet, "Minion of Fear", proc'd "Specter Lifetap", which, if I recall correctly, did only about 83 dmg, without a chance to proc "Prism Skin" either.
Overall a nice pet upgrade.