If a pope should bring fire down from Heaven, Muslems, who put a great weight on miracles, would unite with whomever could do that.
I do need to emphasize to the Catholics on the board, this is not an attack upon devout Catholics, but there will be an apostasy within the Catholic Church that deceive the world.
Rather, since Mutawill and the de-Hellenization of Islam in the 10th century, the belief is that there are no miracles and no science/logic either -- everything is predestined, pre-willed, pre-written. There is nothing but utter fate/destiny.
No "fire from heaven' would convince the Wahabbis -- don't mistake them for Tantrics!