Stomp  

In the non instanced thundercrest isles zone. I have killed a bunch of them, and this is the first time I had this cast on me that I was aware of. The animation he used was to clap his hands when he cast it. Maybe I thought it was just a regular stun from getting hit with it previously and didn't recognize it as special. With a resist check of only -17, it would seem I would have seen a resist for Stomp spell in my spell box but I don't remember seeing it. But this time he was rooted out of melee range when it happened, and I paid more attention.