Given this definition - Anyone at the Vatican come to mind? Perhaps, a Bishop dressed in White ‘we had the impression that it was the Holy Father'

Source: Fr. Johannes Brunsmann, A Handbook of Fundamental Theology, Volume 3, Ed. Arthur Preuss, B. Herder Book Company, 1928, 1929, 1931, 1932, p. 240-241
Membership of the Church – Unbelievers and Professed Heretics – Ecclesia Militans ||
Fr. Johannes Brunsmann, S.V.D., on Public Heretics and Membership of the Church – Ecclesia Militans