Yup, that's where they appear and they are very deceptive. I started attacking one, only getting hit for low damage like a regular earth elemental. Then when it got low on health, it did this area collosal blow on me, stunning me, then it walked up to me and smacked the ghost out of my body with a whopping 100+ damage. Needless to say I was a little surprised but it really explained the "enraged" part.