What just happened?

Do let me know if anybody knows anything about this or encountered it.

I was following wisps in the wildwood and suddenly that circle of wisps around me turned all red and a unique monster spawned I barely managed to see anything cause he teleported about 30 times in 2 seconds and killed me. I was about 5-6k whisps nothing huge.

What the heck was that?

Ah yea, that thing.
Can't remember the name of it, only seen it once.
Did see ppl in global talking about how to deal with it. Answer seemed to be "just deal enough dmg to kill it fast"

I think they call him The Butcher. :-)