I think of it as a body eclipsing the true Church. As a counterfeit church could never actually be PART of the one, Holy, Catholic and apostolic Church. Some can see the true Church in the corona surrounding this body, but many mistake it for the Church out of ignorance.
The term "Conciliar Church" was actually coined by the Cardinal Benelli. And the response of Archbishop Lefebvre? "To whatever extent Pope, Bishops, priests, or faithful adhere to this new Church, they separate themselves from the Catholic Church." To me it is like a cancer affecting the members and even the visible Head.