That was an intense episode. We nearly got to see nearly all the house ghosts (except for Travis, Tate's dad, and Black Dahlia). Violet had every right to be angry with Tate. She already knew about Tate's dark past, but her finding out that Tate raped Vivien just did it for her. Now Vivien is a ghost, too.
That "Krotoan" spell was obviously baloney, and "Go Away" only banishes the ghost temporarily, so Tate will be back next week. Poor Ben, he's all alone now, but for how long?