Rift Mob:The Ghost of Malluma  

I found the Ghost of Malluma, not in the Scoria Pit as it says in the Zone information on this page, but in Malluma Basin. He was at the top of the waterfall, perched on the rocks at around 7495,11578 The ghost is a level 51 elite, and quite difficult to see. I wouldn't have spotted him at all except that I was jumping that waterfall and hit him.

Secondary location at 7504, 11425 (the other waterfall in the area).